Analysing the institutional pressures on shippers and logistics service providers to implement green supply chain management practices

ABSTRACT

This paper applies institutional theory to analyse the institutional pressures (regulatory, market, competitive) experienced by two actors within supply chains: shippers (i.e. logistics buyers) and logistics service providers (LSPs). Both actors are subject to institutional pressures to adopt green supply chain management practices, which could drive shippers to purchase green logistics services from LSPs, and LSPs to provide them. Also, the two actors are influenced by various factors that moderate the level of pressures on them and the responses they undertake. This study examines these pressures and moderators in detail to analyse how they influence green logistics purchasing/providing decisions. Empirical data were obtained from eight individual cases of three shippers and five LSPs. Accordingly, we compare these pressures and moderators based on the actors’ different roles in the supply chain. The findings aim to contribute to advancing the theory through (i) incorporating the roles of the moderating factors and (ii) providing further applications within specific shipper-LSP contexts. Further, this paper aims to assist managers within shipper and LSP organisations by demonstrating how their firm and market characteristics moderate the pressures exerted on them to buy or provide green logistics services, while providing insights on issues influencing their responsiveness.

KEYWORDS:

• Institutional theory
• GSCM
• green logistics
• environmental sustainability
• LSP
• logistics buyers
• case study
• contract logistics

1. Introduction

A growing trend of incorporating green measures into supply chains is observed today in response to the rising global pressures to preserve the planet. Among different supply chain sectors, the logistics and transport sector is considered one of the main contributors to various environmental threats such as air pollution, global warming and resource depletion (McKinnon et al. 2015). Almost 20% of global energy consumption is associated with transportation (IEA 2015). Even worse, the total tonne-kilometres travelled by road freight is expected to triple between 2015 and 2050 due to the latest developments of the world economy and increasing global demands (ITF 2017), leading to further emissions and environmental harm (Grant, Trautrims, and Wong 2015). Such figures expand the burden on logistics services providers (LSPs) to expedite the ‘greening’ process of their logistics functions, given their central position among supply chains and the dependability of other actors on them in carrying out their logistics functions (Colicchia et al. 2013; Rossi et al. 2013). However, LSPs are not the only actors responsible for facilitating green logistics practices; scholars started realising that shippers (i.e. logistics buyers) play an important role as well (see Rogerson 2017; Sallnäs 2016; Wolf and Seuring 2010), as it is shippers who select LSPs and make the choices on where and how locations are set up (Wolf and Seuring 2010).

Due to the significance of shippers’ and LSPs’ roles amid supply chains, investigating what drives their engagement (to either buy or provide green logistics) is garnering increased academic attention. In general, a number of studies focus on what drives supply chain actors to engage in green supply chain management (GSCM) practices (e.g. Walker, Di Sisto, and McBain 2008; Zhu, Sarkis, and Lai 2007), but without providing clear linkages to logistics purchasing/providing decisions. Others, while focusing on logistics, capture what drives shippers to purchase green logistics services (e.g. Björklund 2011) or LSPs to provide them (e.g. Evangelista 2014; Lieb and Lieb 2010; Perotti, Micheli, and Cagno 2015). However, few studies seem to incorporate both actors’ viewpoints concurrently to grasp what the main drivers for facilitating green logistics are. In an effort to investigate what drives LSPs in particular, Kudla and Klaas-Wissing (2012) studied how shippers stimulate LSPs to act sustainably, and how LSPs respond. Although the authors focused on shipper-LSP dyads, empirical data were based only on LSPs’ information. The authors later remarked on instances where even sustainability-proactive shippers have barely integrated logistics purchasing in their sustainability management, stressing the demand for further research to include the shippers’ standpoint. Large, Kramer, and Hartmann’s (2013) survey of shippers similarly found that placing high importance on sustainability measures by shippers does not occur to the same degree when they engage with LSPs.

Other studies that did involve both perspectives (e.g. Björklund and Forslund 2013; Sallnäs 2016; Wolf and Seuring 2010) seem to mainly focus on how environmental practices are coordinated in shipper-LSP relationships, neglecting to take a step backward to outline what motivates the actors’ green engagement. Moreover, when studies focus on shipper-LSP dyads, the role of other stakeholders beyond the buyer and seller (e.g. regulators and competitors) tends to be overlooked, resulting in a somewhat oversimplified analysis.

Based on the reasoning above, the purpose of this paper is threefold: (i) to investigate how the drivers for shippers to engage in GSCM practices are related to demanding green logistics practices from LSPs, (ii) to analyse the importance of shippers’ demands in driving LSPs to implement green logistics practices compared with other influencers such as regulators and competitors, and (iii) to compare what drives shippers and LSPs to engage in green logistics practices (through buying/offering them), given their vital roles in facilitating these practices.

To fulfil the purpose, we will utilise institutional theory to analyse the institutional pressures (i.e. external drivers) on firms to engage in environmental actions. These pressures, within a GSCM context, alternate between regulatory, market and competitive pressures (Zhu and Sarkis 2007). Institutional theorists stress that firm and market characteristics moderate the level of pressure experienced by a firm via either magnifying or diminishing it (see Delmas and Toffel 2008; Gardberg and Fombrun 2006; Levy and Rothenberg 2002). Five of these ‘pressure moderators’ are focused upon in this paper: industry, operating country, visibility, internationalisation and size. One of the major limitations of the theory is that it ignores the role of top management in influencing the environmental responsiveness of a firm (Colwell and Joshi 2013; Dacin, Goodstein, and Scott 2002; Kostova and Roth 2002), thus failing to explain why firms under similar institutional contexts might respond differently. Resolving this is suggested by incorporating the role of managerial commitment in moderating the environmental responsiveness of a firm (Colwell and Joshi 2013; Sharma 2000). We shed light upon such role in this paper through the connotation ‘response moderator’.

This study contributes in advancing the theory through (i) incorporating the influence of pressure/response moderators to engage in GSCM practices, and (ii) providing further applications in specific shipper-LSP contexts. Further, by comparing buyer and seller views on environmental sustainability pressures and moderators, contrasting patterns will emerge based on the actors’ different, and significant, roles in the supply chain, providing further depth through conceptualising how their different institutionalised conditions influence green logistics practices. For the empirical part of this paper, data were collected from a multiple-case study of eight distinct cases, three shippers and five LSPs. The paper aims to assist managers within shipper and LSP organisations by demonstrating how their firm and market characteristics moderate the pressures exerted on them to buy or provide green logistics services, while providing insights on issues influencing their responsiveness.

Section 2 of this paper creates a theoretical framework encompassing the institutional pressures to implement GSCM practices and clarifying the pressure and response moderators. This is followed by constructing the main framework of the study. After section 3 on methods and section 4 on findings, section 5 discusses the findings while cross-matching them with the theory. Lastly, section 6 draws the main conclusions together with discussing the limitations and avenues for further research.

2. Theoretical framework

2.1. Institutional pressures to implement GSCM practices

Institutional theory highlights the role of social and cultural pressures that affect organisations’ practices and structures in order to gain legitimacy or acceptance within the society (Scott 1987). DiMaggio and Powell (1983) stress that managerial decisions within organisations are primarily influenced by three institutional forces: coercive, normative and mimetic. The application of the theory is encouraged in operations management research (Ketokivi and Schroeder 2004), as well as environmental management studies (Delmas and Toffel 2004; Hoffman 2001), which has inspired others to utilise the theory in the GSCM context to explain why firms in a supply chain adopt environmental practices (see Wu, Ding, and Chen 2012; Zhu and Sarkis 2007; Zhu, Sarkis, and Lai 2013). According to Zhu and Sarkis (2007), institutional forces within GSCM are projected by regulatory (coercive), market (normative) and competitive (mimetic) pressures. Colicchia et al. (2013, 198) define institutional drivers within GSCM as ‘external forces that motivate companies to adopt environmental initiatives coming from regulators, the market and competitors coherently with the institutional theory’.

Regulatory pressure can be defined as ‘the coercive pressures driving the implementation of GSCM by (…) managers in hopes of improving their performance’ (Zhu, Sarkis, and Lai 2013, 107). An example of this type of pressure is when governmental agencies enforce certain policies or taxation on firms to limit the environmental impact associated with their business (Seuring and Müller 2008; Walker, Di Sisto, and McBain 2008). Market pressure, in turn, is defined by Zhu and Sarkis (2007) as the pressure from customers on suppliers to act sustainably, in which firms demand that their suppliers comply with environmental and social norms (Seuring and Müller 2008), such as acquiring environmental management system certifications like the ISO 14001. Last, competitive pressure is emphasised when firms mimic green strategies adopted by successful firms in their field in an attempt to increase their legitimacy, enhance their performance, and gain competitive advantages (Colicchia et al. 2013; Markley and Davis 2007).

2.2. Firm and market characteristics as pressure moderators

The level of institutional pressures exerted on firms to implement environmental practices varies across different countries and industries due to diversified market characteristics (Rowley and Berman 2000). In light of this, several studies particularly confirm the role of industry (Gardberg and Fombrun 2006; Hoffman 2001; Rowley and Berman 2000; Sweeney and Coughlan 2008) and operating country (Delmas 2002; Srivastava and Srivastava 2006; Yalabik and Fairchild 2011) in moderating the level of institutional pressures. However, even for companies operating within the same institutional context, the level of pressures exerted on them fluctuates due to their distinct firm characteristics, as noted by Delmas and Toffel (2004, 219). Accordingly, the literature highlights the role of visibility (Delmas and Toffel 2004; Gardberg and Fombrun 2006; González-Benito and González-Benito 2006; Hoejmose, Brammer, and Millington 2012; Rowley and Berman 2000), internationalisation (Delmas and Toffel 2004; Levy and Rothenberg 2002; Zyglidopoulos 2002), size (Arvidsson 2010; Delmas and Toffel 2004; Rowley and Berman 2000; Zhu and Sarkis 2007), historical environmental performance (Delmas and Toffel 2004; Rowley and Berman 2000), and brand reputation (Rowley and Berman 2000) in moderating the level of pressures on firms. We sought experts’ opinions to limit the number of factors in this study, which was mainly to: (i) set the boundaries for this research, and (ii) to ensure relevance of the factors in the contract logistics context (see Methods for more details). We selected the factors that overlapped between the literature and experts’ opinions (Table 1), resulting in the following five firm and market characteristics: industry, operating country, visibility, internationalisation and size. These are considered as pressure moderators in this study, and each will be explained in detail next.

Table 1. Factors to be considered under pressure moderators.

	Literature	Experts’ opinions
Industry^a	Gardberg and Fombrun (2006), Hoffman (2001), Rowley and Berman (2000); Sweeney and Coughlan (2008)	✓
Operating country^a	Delmas (2002), Srivastava and Srivastava (2006), Yalabik and Fairchild (2011)	✓
Visibility^a	Delmas and Toffel (2004), Gardberg and Fombrun (2006), González-Benito and González-Benito (2006), Hoejmose, Brammer, and Millington (2012), Rowley and Berman (2000)	✓
Internationalisation^a	Delmas and Toffel (2004), Levy and Rothenberg (2002), Zyglidopoulos (2002)	✓
Size^a	Arvidsson (2010), Delmas and Toffel (2004), Rowley and Berman (2000), Zhu and Sarkis (2007)	✓
Historical environmental performance	Delmas and Toffel (2004), Rowley and Berman (2000)	–
Brand reputation	Rowley and Berman (2000)	–
Enlistment on stock exchange	–	✓

^aSelected due to the overlap between literature and experts’ opinions.

2.2.1. Industry

Different industries have unique supply chains and thus are subject to distinct environmental demands. Companies whose core activities are associated with high environmental impact, such as those operating in the oil and steel industries, are expected to demonstrate a high level of responsibility in the way they conduct their business (Gardberg and Fombrun 2006; Hoffman 2001). In contrast, companies with less of an environmental impact, such as banks or insurance companies, experience lower expectations and pressures to act responsibly (Gardberg and Fombrun 2006). To verify this, Sweeney and Coughlan (2008) performed a content analysis on sustainability reports of 28 firms operating within different industries. Their results highlight a significant variation in firms’ environmental and social disclosure due to different stakeholders’ expectations across those industries.

2.2.2. Operating country

The country where a company operates plays an important role in moderating the level of pressure exerted on it. Yalabik and Fairchild (2011) find that firms operating in developed countries are under higher competitive pressures than firms operating in countries with more relaxed environmental laws. A different outcome was reported by Delmas (2002), who deployed an institutional viewpoint to study the drivers to implement the ISO 14001 certificate in different parts of the world. Her results show that a significant number of companies have adopted ISO 14001 in Western Europe and Asia, whereas very few American companies have. She relates this to the effect of regulatory, normative and cognitive aspects of the institutional environment in a specific country on the costs and potential benefits of acquiring the certificate. Another example is provided by Srivastava and Srivastava (2006), who argue that reverse logistics practices are ‘regulatory-driven’ in Europe, ‘profit-driven’ in the United States, and in an emerging phase in other parts of the world such as India.

2.2.3. Visibility

It is commonly acknowledged in the literature that ‘highly visible’ firms that operate in business-to-consumer (B2C) markets engage in environmental practices more intensively and proactively than those operating in business-to-business markets (B2B) (Delmas and Toffel 2004; Gardberg and Fombrun 2006; González-Benito and González-Benito 2006). The reason is that B2C actors have stronger incentives to act sustainably, being exposed to relatively high stakeholder expectations (González-Benito and González-Benito 2006). Hoejmose, Brammer, and Millington (2012) attempted to authenticate this argument by surveying 340 buyer-supplier relationships (i.e. B2B relationships). They found that adopting green practices is rather ‘neglected’ in the B2B sector due to the distance from end consumers and lack of visibility. However, they suggest that facilitating successful environmental practices in B2B contexts requires sufficient top management support on green issues. Within shipper-LSP relationships, Kudla and Klaas-Wissing (2012) find that shippers operating in B2C and ‘reputation-sensitive’ markets in particular demonstrate high interest in LSPs’ sustainability programmes.

2.2.4. Internationalisation

Whether a particular company is operating locally or internationally has an influence on the level of pressure exerted on it. Zyglidopoulos (2002) and Levy and Rothenberg (2002) argue that multinational companies are often subject to higher standards for social and environmental responsibility than their national counterparts due to their exposure to additional pressures from stakeholders in all the countries where they operate. Zyglidopoulos (2002) links the formation of a more restrictive multinational atmosphere in terms of social and environmental responsibility to two mechanisms: international reputation side effects (i.e. judgement by international reputation even if a certain subsidiary operates responsibly) and foreign stakeholder salience (i.e. additional pressure exerted by stakeholders within a subsidiary’s location).

2.2.5. Size

Delmas and Toffel (2004) stress that large market leaders in terms of revenue, market share or total assets are more prone to stakeholders’ pressure to act sustainably than small firms. This is because large companies are more exposed to public scrutiny and are thus likely to experience more social and political pressures (Arvidsson 2010). Zhu and Sarkis (2007) stress that regulatory and market pressures may influence large firms, whereas small firms are more likely to be influenced by competitive pressures. Within the logistics industry, Kudla and Klaas-Wissing (2012) argue that large LSPs are subject to slightly more intensive market pressure to act sustainably than are small and medium-sized LSPs.

2.3. Managerial commitment as a response moderator

Institutional forces are ‘transformed’ once they penetrate a firm’s boundary, because they are filtered and interpreted by managers in correspondence to the firm’s unique background and culture (Levy and Rothenberg 2002; Liu et al. 2010). This is crucial; when two firms are subject to the same level of pressure, they tend to respond differently (Sharma and Starik 2004). Two questions, however, arise alongside this notion. First, what are the factors that influence the managerial responsiveness to pressures? Second, do managers simply play reactive roles by responding to the pressures imposed, or is there room for proactivity? Institutional theory does not seem to provide answers for neither of these questions, as it ignores the role of managerial commitment in influencing the firm’s responsiveness (Colwell and Joshi 2013; Dacin, Goodstein, and Scott 2002; Kostova and Roth 2002), thus diminishing the chance of proactivity within environmental decisions.

Institutional theorists have both recognised these issues and proposed ways to overcome them. That is, it is acknowledged that organisations differ in the way they pursue a particular institutional practice and in their ability to institute organisational change (Delmas and Toffel 2008; Hoffman 2001). We draw from different sources of environmental management and GSCM literature (Ahmad et al. 2016; Branzei and Vertinsky 2002; Campbell 2007; Carter and Dresner 2001; Chan et al. 2012; Dai, Montabon, and Cantor 2014; Greenwood and Hinings 1996; Hillary 2004; Kudla and Klaas-Wissing 2012; Lieb and Lieb 2010; Maignan and Ralston 2002; Marchet, Melacini, and Perotti 2014; Piecyk and Björklund 2015; Sharma 2000; Zhu, Sarkis, and Geng 2005; Zsidisin and Siferd 2001) five factors that are particularly critical in influencing managers’ commitment in their response to external pressures: (i) interpretation of pressures, (ii) top management support, (iii) economic condition, (iv) organisational structure, and (v) collaboration opportunities. We argue that these factors influence the role of managerial commitment in moderating the firm’s environmental responsiveness (via adopting GSCM practices), in which the higher the commitment by managers, the higher the expected responsiveness, which could potentially lead to proactivity. Like the case with pressure moderators, selecting these factors was supported by experts’ opinions (Table 2). Each of the selected factors is explained in detail next.

Table 2. Factors to be considered to influence the response moderator.

	Literature	Experts’ opinions
Interpretation of pressures^a	Branzei and Vertinsky (2002), Carter and Dresner (2001), Maignan and Ralston (2002), Sharma (2000)	✓
Top management support^a	Ahmad et al. (2016), Dai, Montabon, and Cantor (2014), Hillary (2004), Zhu, Sarkis, and Geng (2005), Zsidisin and Siferd (2001)	✓
Economic conditions^a	Ahmad et al. (2016), Campbell (2007), Chan et al. (2012)	✓
Organisational structure^a	Ahmad et al. (2016), Kudla and Klaas-Wissing (2012)	✓
Collaboration opportunities^a	Lieb and Lieb (2010), Marchet, Melacini, and Perotti (2014), Piecyk and Björklund (2015)	✓
Risk management	Ahmad et al. (2016)	–
Family vs. professionally-run	–	✓
Education of managers	–	✓

^aSelected due to the overlap between literature and experts’ opinions.

2.3.1. Interpretation of pressures

Playing a reactive role by solely complying with pressures does not guarantee enhanced environmental performance. These pressures need to be coupled with a proactive attitude to trigger successful sustainable projects (Branzei and Vertinsky 2002; Carter and Dresner 2001). Such proactivity depends on whether managers perceive pressures as threats or opportunities, argues Sharma (2000), whose survey aimed at identifying the factors affecting managers’ interpretation of pressures. He finds that managerial interpretation of environmental issues as opportunities is positively correlated with implementing environmental strategies, in which interpreting them as opportunities relies on two elements: (i) the legitimacy of environmental issues on hand, and (ii) the degree of discretionary slack afforded to managers to deal with sustainability concerns. Likewise, Maignan and Ralston (2002) argue that managers are motivated to behave responsibly when they believe that such behaviour enhances the financial performance of their firms.

2.3.2. Top management support

Top management is perceived as a key influencer in shaping organisational values and strategies (Hambrick and Mason 1984; Hart 1992). This indicates that when top management’s focus is directed towards green objectives, managers and employees within different levels of the firm tend to engage further in green initiatives (Ahmad et al. 2016; Dai, Montabon, and Cantor 2014; Zsidisin and Siferd 2001). Zhu, Sarkis, and Geng (2005, 453) argue that top management should be ‘totally committed’ to ensure complete environmental excellence. In contrast, lack of top management support is viewed as a main barrier to successful environmental practices (Hillary 2004). However, the influence of top management support seems to be sensitive to the visibility of the firm: Hoejmose, Brammer, and Millington (2012) find that top management support is a key driver for engaging in GSCM practices among B2B firms but less important among B2C ones, reasoning that GSCM practices are not constrained by strategic imperatives in the B2B sector.

2.3.3. Economic conditions

The economic conditions of a company (particularly financial performance and level of competition) influences the chance that its managers will behave responsibly (Ahmad et al. 2016; Campbell 2007; Chan et al. 2012). According to Campbell (2007), experiencing weak financial performance or too high/low level of competition minimises this chance, whereas having a ‘healthy’ economy and a moderate level of competition often increases the chance. The main reason relates back to the slack resource theory (Ullmann 1985; Waddock and Graves 1997), which entails that firms who are less profitable possess fewer resources to spare for social and environmental activities than firms that are more profitable (see Orlitzky, Schmidt, and Rynes 2003 for more details). However, Campbell (2007) also argues that economic conditions are less effective in influencing mangers’ decisions when a company is subject to high regulatory and monitory pressures.

2.3.4. Organisational structure

Organisational structure and complexity also influence managerial responsiveness to pressures. Ahmad et al. (2016) emphasise the importance of cross-functional integration between different departments to counter such complexity and successfully incorporate GSCM practices. Taking the logistics industry as an example, Kudla and Klaas-Wissing (2012) argue that large LSPs can be slow to react to sustainability requirements due to their complex organisational structures and inefficient internal communication among their departments (e.g. sales, operations, sustainability). In contrast, small and medium-sized LSPs, such as family-run companies, are more likely to behave responsibly due to clear and flat hierarchies, direct top management support of sustainability actions and altruistic drivers (ibid.).

2.3.5. Collaboration opportunities

Keeping the focus on the logistics industry, many scholars (e.g. Lieb and Lieb 2010; Marchet, Melacini, and Perotti 2014; Piecyk and Björklund 2015) argue that it is mostly large LSPs that adopt environmental initiatives, whereas small and medium-sized LSPs lag behind. The main reason is that large LSPs enjoy a better access to partnerships and collaborations on sustainability efforts, where they work more closely with customers, regulators, transporters, universities, and trade associations, which keeps them abreast of the latest advancements due to greater access to data, experience and larger networks (Lieb and Lieb 2010).

2.4. Conceptual framework

Figure 1 demonstrates the main conceptual framework of this study. It depicts the three types of institutional pressures (regulatory, market, competitive) that drive firms to adopt GSCM practices, in which the level of these pressures is moderated by firm and market characteristics (industry, operating country, visibility, internationalisation, size). As explained earlier, firms tend to respond differently even if they are exposed to the same level of pressure, due to the moderating effect of managerial commitment on environmental responsiveness. The role of managerial commitment takes place after the pressures cross the firm’s boundary, and it is influenced by the factors: interpretation of pressures, top management support, economic conditions, organisational structure and collaboration opportunities.

Figure 1. Institutional pressures and pressure/response moderators for GSCM practices.

In general, the framework can be applied to any company within the supply chain that is expected to engage in GSCM practices, which typically includes shippers and LSPs, since they are both active players in supply chains, and both are subject to institutional pressures to act in an environmentally friendly manner (which comprises buying/offering green logistics). Certainly, the level of pressure experienced to engage in green logistics practices differs among them, mainly due to their diverse industries as well as their different roles as buyer or provider.

To further explain the framework in relation to shippers and LSPs: shippers are influenced by institutional pressures to implement GSCM practices, whether these practices are conducted internally within a firm’s boundary or externally through collaboration with external partners (Zhu, Sarkis, and Lai 2013). External GSCM practices covers purchasing green logistics services (Min and Galle 1997; Pazirandeh and Jafari 2013). Seuring and Müller (2008) argue that companies hand the pressure down to their suppliers through the downstream supply chain. Following this logic, shippers transfer a portion of the pressure exerted on them onto LSPs by demanding green logistics services.

LSPs are also influenced by institutional pressures to implement green logistics practices (Colicchia et al. 2013; Kudla and Klaas-Wissing 2012). For them, the pressure from their shippers constitutes market pressure (Colicchia et al. 2013), i.e. LSPs’ business customers are always shippers. We relied on Perotti et al. (2012) to provide examples of green logistics practices, since their extensive literature review highlights the main environmental initiatives implemented by LSPs while grouping them into distinct categories (Table 3). Note that these practices could be implemented in response to pressures experienced by LSPs (e.g. shippers’ demands) or simply triggered by LSPs’ proactive behaviour.

Table 3. Examples of LSPs’ green logistics practices (Perotti et al. 2012).

Category	Examples
Distribution strategies and transportation execution	(Re) design of logistics system components for higher environmental efficiency
	Environmentally friendly facility location
	Use of alternative fuels
	Mode selection based on ‘eco-friendly’ parameters
	Use of more recent/less polluting vehicles
	Effective shipment consolidation and full vehicle loading
	Routing systems to minimise travel distances
Warehousing and green building	Attention to construction materials (e.g. use of recycled concrete, steel, asphalt and other materials)
	Building thermal insulation
	Installing skylights to utilise natural light as a source of interior illumination
	Energy-efficient lighting systems
	Energy-efficient material handling equipment
	Use of alternative energy sources (e.g. solar or photovoltaic panels)
	Water systems (e.g. plants and landscaping materials that minimise water waste)
Reverse logistics	Waste transport and disposal
	Material recycling whenever possible
	Consumption reduction whenever possible
	Material reuse whenever possible
Eco-design and packaging	Packaging design for reduced environmental impact
	Packaging recycling or reuse
	Use of biodegradable materials
Cooperation with shippers	Cooperation on eco-design
	Cooperation on cleaner production and distribution
	Cooperation for green packaging
Internal management	Commitment to GSCM from senior managers
	Cross-functional cooperation for environmental improvements
	Total quality environmental management
	Environmental compliance and auditing programmes
	Environmental Management Systems (e.g. ISO 14001 certification)
	Environmental performance measurement and monitoring
	Use of green IT (e.g. reduction in server numbers, use of green software)
	Publicise environmental efforts/accomplishments
	Development of a formal environmental sustainability statement for the company

3. Methods

Case studies enable gaining a profound understanding of logistics antecedents (Frankel, Naslund, and Bolumole 2005) and are particularly encouraged when investigating interactions among shippers and LSPs (Selviaridis and Spring 2007). Because this research aims to provide an in-depth investigation onto how institutional pressures influence shippers and LSPs to engage in green logistics, we chose a case study approach. Ketokivi and Choi (2014) classify case research into three distinct modes: theory generation, theory testing and theory elaboration. The latter appears to appropriately represent this study; theory elaboration implies applying an existing general theory to an under-researched context to attain premises that can be used in aggregation with the general theory (Ketokivi and Choi 2014). One might question why theory testing was not the selected approach; theory testing requires obtaining sufficient premises already in the theoretical phase of the research, and then testing them empirically (Ketokivi and Choi 2014). Since the context of this study (i.e. the influence of pressures and moderators on shippers/LSPs) is not well-established in the contract logistics literature yet, forming sufficiently detailed premises to deduce testable hypotheses was not achievable at the current stage.

Due to the lack of well-developed theoretical frameworks that identify the factors to be included under pressure/response moderators on shippers/LSPs in particular, we expanded our research by looking into broader disciplines, mainly within the domains of environmental management and GSCM. Various factors were found under these disciplines (see Tables 1 and 2). To ensure covering the factors that are most relevant to our study, we sought experts’ opinions, in a fashion similar to a Delphi approach. This helped in enhancing the content validity of the selected factors (Flynn et al. 1990), and set the boundaries for the research. Four experts with substantial experience in the supply chain management and contract logistics fields were asked to identify (i) the main firm and market characteristics that would moderate the pressures on firms to adopt GSCM practices, and (ii) the main factors that influence firms’ managerial commitment to engage in such practices. The questions were asked in subsequent rounds until a consensus among the experts was reached, in line with Flynn et al. (1990). Then, we highlighted the factors that overlapped between the literature and experts’ opinions, yielding five factors under each subgroup, as shown in Tables 1 and 2. However, limiting the number of factors, although useful for focusing the research, bears a limitation of excluding other factors that might be of relevance. We therefore encourage testing the influence of the other extracted factors (e.g. brand reputation, historical environmental performance) in further studies, which might offer an expansion to our framework.

3.1. Case selection

Multiple-case studies are generally favoured over single cases because they enhance the external validity and rigour of the research (Yin 2009). Accordingly, we approached eight case companies, three shippers and five LSPs. Not having dyadic relationships as the unit of analysis enabled us to focus on the two supply chain actors separately through analysing the pressures and moderators experienced by each as a first step, and then drawing comparisons between them based on their different buying/selling roles as a second step. Further, limiting the study to dyads would restrict conceptualising the externalities influencing each of the actors in their GSCM decisions, as shippers and LSPs (particularly large ones) often form numerous partnerships with various logistical partners.

Finding suitable cases with resemblances between them is required in the case selection process to enhance the generalisability of outcomes (Yin 2009). Hence, all the approached shippers are large, possess known brands, demonstrate sustainability awareness on their business profile, operate globally and outsource logistics activities to LSPs. By this, they exemplify typical multinational companies that pay attention to environmental sustainability and may reflect this in their logistics purchasing behaviour. However, since this research suggests that various firm characteristics and backgrounds (i.e. pressure and response moderators) influence institutional pressures and environmental responsiveness, we also intended to discover contrasting patterns in the data sample when selecting the cases (in line with Eisenhardt and Graebner 2007). Accordingly, the three shippers in the sample operate in diverse industries (mining and materials technology, telecommunication equipment, food and salted snacks) that are associated with varying environmental risks and different proximities to end consumers. By the same logic, the approached LSPs have different sizes, geographical coverages and product portfolios (within logistics offerings), whereas all of them exhibit environmental sustainability alertness on their websites and deal with a wide range of shippers (small and large ones). The contrasting characteristics of the LSPs allowed analysing the different pressures and moderators, yet the LSPs are expected to offer green logistics services to a diversity of customers with different green demands. Table 4 provides information about the cases and their participants, noting we agreed with them on anonymity. The business units in the sample operate within Swedish and German markets, two countries that actively engage in environmental debates (EPI 2016), which appears relevant to our purpose. However, we recognise the risk of limited generalisability due to confining the sample to these countries. Even among the considered industries for shippers, each was represented by one case only, thus generalisation cannot be claimed on their entire industries. In addition, due to the extreme difficulty in finding cases that cover all firm and market characteristics provided in our framework (Figure 1), our study will mainly illustrate the framework and elaborate the theory (as mentioned earlier). Further empirical testing for the framework is recommended at a later stage.

Table 4. Case companies and participants.

Shippers	SI	SII	SIII
Turnover	€1,300 million	>€20,000 million	€2,000 million
No. of employees	6,500	109,000	8,000
Origin	Sweden	Sweden	Germany
Geographical coverage	Global	Global	Europe
Industry	Mining and material technology	Telecommunication equipment	Food and snacks
Segment	B2B	B2B	B2B and B2C
Participant: job title/office	SI-I: Global logistics manager/Sweden SI-II: Global freight and customs manager/Sweden	SII-I: Head of distribution management/Sweden SII-II: Distribution and logistics industrialisation manager/Sweden	SIII-I: Supply chain manager/Germany SIII-II: Transport manager/Germany
Secondary data	CSR report Website	CSR report Supplier CoC Website	CSR report Website

Table

LSPs	LSPI	LSPII	LSPIII	LSPIV	LSPV
Turnover	€19,700 million	€57,000 million	€62 million	€31 million	€1.6 million
No. of employees	95,000	500,000	1,000	150	50
Origin	Germany	Germany	Sweden	Sweden	Sweden
Geographical coverage	Global	Global	Local	Local	Local
Logistics focus	Integrated logistics solutions	Integrated logistics solutions	Warehousing, material handling, value-added services	Heavy goods transportation	Integrated logistics solutions
Segment	B2B and B2C	B2B and B2C	B2B	B2B	B2B
Participant: job title/office	LSPI-I: CEO/Sweden LSPI-II: Environmental director/Sweden LSPI-III: Sales director/Sweden LSPI-IV: Sales manager/Sweden	LSPII-I: Sustainability director/Germany LSPII-II: Environmental manager/Sweden LSPII-III: Operations manager/Germany	LSPIII-I: CEO/Sweden LSPIII-II: COO/Sweden LSPIII-III: Head of corporate responsibility (CR)/Sweden	LSPIV-I: CEO/Sweden LSPIV-II: Project manager/Sweden	LSPV-I: CEO/Sweden LSPV-II: Logistics and customer support/Sweden
Secondary data	CSR report Website	CSR report Website	CSR report Website	Website	Website

3.2. Data collection and analysis

Data were collected mainly from interviews, as is common with case studies (Eisenhardt and Graebner 2007). A total of 20 semi-structured in-depth interviews were conducted, in line with Yin (2009). For shipper companies, logistics and supply chain managers were interviewed, and those are acquainted with their companies’ sustainability strategies and responsible for procuring logistics services from LSPs. In turn, LSPs’ participants were mainly chief executives and environmental directors who interact with shippers (and governmental actors) and engage in environmental discourse with them. More information about the participants can be found in Table 4. Each interview lasted one to two hours, either face-to-face or via Skype (depending on accessibility).

The interview questions aimed to grasp the participants’ perceptions within six major categories:

1. General inquiry about the company and the participant’s role

2. General inquiry about environmental commitments adopted by the company

3. Main motives for adopting GSCM practices in general, and for purchasing green logistics services in particular (for shippers)

4. Main motives for conducting green logistics services (for LSPs)

5. Detailed questions about regulatory, market and competitive environmental sustainability pressures experienced by the company

6. Detailed questions about how firm’s characteristics and internal settings influence the pressures and responsiveness

7. Detailed questions about the company’s logistics partners (shippers/LSPs) and their environmental sustainability engagement with the company

17 of the interviews were permitted to be recorded, and all were backed by note-tacking. All interview recordings were fully transcribed and electronically filed to establish a trail of evidence (Yin 2009). The information obtained from the interviews was coded into different categories based on related subject areas, as advised by Voss, Tsikriktsis, and Frohlich (2002). The software NVivo was used for the coding process, allowing multi-layer sub-categorisation, which in turn supported the analysis process. The categorisation was based on: (i) the role of the case company (shipper/LSP), (ii) the specific case company and (iii) the factors covered in the conceptual framework (Figure 1). This allowed us to specify how each of the pressures and moderators influenced the actors’ green engagement on a case-wise and actor-wise basis.

There are two commonly recognised forms for determining institutional pressures: perceptual measures (based on participants’ viewpoints) and objective measures (based on private/public data sources). Capturing both is suggested to gain an inclusive understanding of the pressures (Delmas and Toffel 2004). However, perceptual measures often correlate with objective ones (Dawes 1999), and have been widely adopted in environmental management studies (e.g. Henriques and Sadorsky 1996; Min and Galle 1997; Zhu and Sarkis 2007). We assessed the pressures on firms through analysing the perceptions of the interviewed participants. To provide adequate depth for such analysis, we moved one step beyond determining whether the pressures are high or low. That is, we clustered the pressures into four categories based on their (i) timeliness, and (ii) effectiveness (see section 4.3 for details).

Information obtained from category vii (in interview questions) was used to further validate how the characteristics of an actor could moderate the pressures experienced by it based on the other actor’s viewpoint. For example, if LSPs indicated that large shippers are more demanding for green logistics services than small ones, such an argument provided supporting evidence for the shippers’ pressure moderator ‘size’.

The analysis of the data was carried out along two steps: within-case and cross-case, in compliance with Eisenhardt (1989). The within-case analysis entailed writing up a storyline for each of the cases, whereas the cross-case step facilitated: (i) inspecting the cases against each other and (ii) matching evidence with the established theory. To facilitate the cross-case analysis, we constructed two charts (one for each actor) that depict the association of each of the cases with the studied factors (available in section 4.3). In addition, two tables (Table A1: Shippers; Table A2: LSPs) that summarise the findings from the cases are provided in Appendix.

To secure secondary data and enable triangulation, we accessed all the companies’ websites together with their corporate social sustainability (CSR) reports and supplier codes of conducts (CoC) – if available. The information obtained from these sources helped us to further validate the interviews’ information. For example, if participants from a shipper company expressed that no pressure on green logistics is passed down onto their LSPs, secondary documents (e.g. supplier CoC) were checked to validate this assertion.

The research material was sent out to the participants to ensure a correct understanding of their case-related data and to gain their final approval. Additionally, previous drafts of this paper were revised by research colleagues acquainted with the subject, which helped in reducing the potential bias of subjective analysis that is common in qualitative research.

4. Findings

This section presents a case-by-case summary of the findings (4.1: Shippers; 4.2: LSPs), followed by a cross-case representation (4.3).

4.1. Shippers

4.1.1. SI

The pressures on this Swedish global mining and materials technology firm to engage in environmental actions are mainly split between market (customers) and regulatory pressures – the former seems to dominate in driving the company’s green engagement. In contrast, competition was not expressed as an important driver for its green actions today; the global freight and customs manager noted, ‘since we’re B2B, I still think the bottom line [i.e. service level, cost] is more interesting for our customers, but environmental concerns will come more and more, and some customers will start pushing us soon in that area’. Environmental policies mainly concern the company’s production processes due to the high energy consumption and environmental impact associated with the steel and mining industry. This caused the firm to mainly direct its environmental focus to internal production issues. In terms of green logistics purchasing, operating from Sweden seems to stimulate its ambition; the participants expressed a willingness to comply with the Swedish target to reach a fossil-free transportation sector by 2030. In contrast, one participant explained how environmental logistics policies are more relaxed in, for example, Eastern and Southern European countries. This led to observing a lack of understanding of the company’s green demands by LSPs operating in those regions. A top managerial vision to preserve the environment triggers the company’s green initiatives, but the operationalisation of such initiatives in the logistics procurement process is difficult due to a complex organisational structure, as one participant noted, ‘we have four departments managing our logistics functions: sales, freight, finance and production, where they often have contradicting objectives when it comes to sustainability’. For example, the sales unit would prefer the fastest transport alternative to satisfy the customer, whereas the freight unit favours consolidating shipments to minimise cost. The company aims to compensate for its large environmental impact by demanding green logistics services from its LSPs, which comprises requesting trucks that meet high Euro standards and detailed calculations of CO₂ emissions. Whereby, particularly large and global LSPs excel in complying with such demands. This shipper is an active participant in several workshops that shed light on green transport challenges, and these are often attended by LSPs, consultants and governmental representatives. Also, a willingness to pay extra for green logistics solutions was expressed once a direct relationship between cost and environmental performance was clarified by LSPs, though LSPs often lag in this area.

4.1.2. SII

This Swedish global telecommunication equipment provider finds the regulatory pressures exerted on it to engage in green logistics somewhat ‘loose’ and ‘could have been tougher’, as expressed by the head of distribution management. He also explained that the company is ahead of the environmental policy curve in most of the countries where it operates, although policies in developed European countries noticeably exceed those in developing ones. Regarding market pressure, customers’ green demands often concern the end product, due to the high energy consumption of telecom equipment, which directs the focus towards eco-design approaches. Moreover, SII’s customers (i.e. telecom operators) are increasingly requesting energy-efficient telecom equipment and networks powered by renewable energy grids in order to enhance their green image for their end users. Top management’s vision to preserve the environment is one of the main drivers for the company’s green engagement, which was emphasised in the company’s core values. In contrast, competition does not seem to be a driver for GSCM today (though expected to be in the future), nor to prioritise purchasing green logistics from LSPs, which was emphasised by one participant’s statement: ‘when I talk to the industry, most companies are acting in a similar way as us, they think it [the environmental concern] is important, but when they choose a global LSP to work with, it’s not the number one concern’. The company takes a global perspective when aiming to reduce the environmental impact associated with its logistics activities, which comprises utilising rail networks across Asia, providing technologies for vessel companies to help reduce their fuel consumption and reducing reliance on air shipments. However, the company puts ‘little’ pressure on LSPs to provide green solutions (i.e. no explicit green demands are in place), whereas cost and service levels occupy the highest priorities when selecting LSPs. However, one participant felt that more pressure on LSPs is needed to facilitate green improvements.

4.1.3. SIII

This German food and snacks producer faces tough regulatory pressures to implement environmental standards within the food production processes (e.g. reducing water consumption and chemical usage) due to the sensitivity of the food industry and the extensive scrutiny on it. Yet, little focus is directed towards how logistics functions should be handled. Logistics-related environmental policies were described as ‘not strict enough’. These limited policies are transferred without modification to LSPs, for example by requesting a certain type of Euro class trucks that are required by German laws. Competition was not perceived as a driver for GSCM nor green logistics purchasing. The company’s business customers (i.e. supermarket chains) do not prioritise green issues when goods are transported, because the focus is only on price and lead times. This has led the company to neglect such criteria when purchasing logistics services from its LSPs. The same issue was observed with its end consumers (i.e. buyers of snacks), whose interests do not stimulate the company’s GSCM nor green logistics purchasing initiatives. In addition, focusing only on price in negotiations with LSPs was partly linked to the company’s new organisational structure. As the supply chain manager stated, ‘the negotiations with our freight forwarders are moving out from our logistics department into the procurement department (…) this means, for this other department, that it’s not really about operations, and doing business is all about the price’. The company has a strong top managerial focus on efficiencies and cost reduction when dealing with its LSPs, whereas environmental issues are seen as a ‘luxury’ topic. This lack of green engagement relates back to a tough economic condition experienced by the company, due to current high competition and tight profit margins within its segment.

4.2. LSPs

4.2.1. LSPI

This large global LSP offers integrated logistics solutions. Generally, operating in the logistics industry places it under high pressure. As the CEO stated, ‘the logistics industry is not very cherished because we’re creating pollution, traffic jams, noisy environment, etc. So everybody is pointing at us’. The participants expressed an influence by all three pressure sources (regulatory, market, competitive) to engage in green logistics. Of these, market pressure seems to dominate. This was evident by the sales director’s statement, ‘if the customer is willing to reduce its carbon footprint, the company will contribute as a response to the customer’s demands’. Further, it was explained that the company has played a proactive role during several endeavours (e.g. creating techniques to increase the load factor in trucks), but such proactivity was stimulated by the increasing customers’ demands that pushed the company to ‘think outside the box’, as stressed by the CEO. However, the participants expressed that most customers do not prioritise environmental concerns when buying logistics services, but the ones who do are often the large companies who also contribute to the majority of this LSP’s turnover. Besides size, several characteristics were outlined for environmentally conscious customers: operating in B2C sector, possessing popular consumer brands, enlisting on the stock exchange, operating internationally, operating in industries associated with high environmental impact via production processes (e.g. steel and pulp industries), or via their end products. All these actors ‘have much focus from outside on what they’re doing and cannot neglect sustainability’, as stated by the sales director. In addition, companies who are exceeding their financial targets are seen as more demanding of green logistics in comparison to underperforming ones, who tend to solely focus on cost reductions in their negotiations with this LSP. Operating from Sweden appears to play a role as well, where one participant explained that Nordic customers (including small and medium-sized ones) are at the forefront in demanding green logistics, which is not the case with U.S. or Asian customers, for instance. The role of competition in driving the LSP’s green engagement was acknowledged only when dealing with large companies, as noted by one participant, ‘if you want to be on the list of potential suppliers for the big companies then you have to have a program for sustainability’. Regulatory pressures do not seem central in driving the LSP’s green actions, as it considers the current policies rather ‘soft’ (e.g. no specific law to limit CO₂ emissions is in place), and the LSP perceives itself way ahead of the current policies. Also, one participant explained that regulatory demands might have a ‘political touch’, making them less realistic and applicable in the logistics industry (e.g. prioritising railroad solutions at the expense of other efficient transport modes). The LSP has initiated a number of collaborative green projects with several organisations such as government agencies, universities, truck manufacturers and even logistics competitors. This enabled gathering all relevant stakeholders under one roof to trigger effective discussions. There is a ‘strong voice’ from top management that triggers sustainability initiatives across the LSP's departments, as conveyed by the environmental manager. Yet, such values seem associated with financial incentives, as stated by the CEO, ‘to be profitable tomorrow, we are convinced that we have to do a lot of proactive things; in the end we’re not giving away anything’.

4.2.2. LSPII

This large and global LSP engages in green logistics practices to satisfy three main stakeholder groups: customers, employees and investors, whereas legislators occupy a secondary rank, as expressed by the sustainability director. Several customers seem not only to request green solutions but also willing to pay a surplus charge for them. These are often the large customers, the ones incorporating clear sustainability values in their own vision, or the ones operating in B2C segments who are close to the end users. One example is the e-commerce customers, who focus on green measures to ensure that the purchased logistics services are clearly branded on the parcels delivered to their recipients. Meanwhile, the ones operating in B2B contexts tend to demand green services ‘selectively’. Regarding regulatory pressures, the company sees itself ‘beyond what every government is demanding’, which causes sort of ‘a comfortable situation’, although some countries have tougher regulations than others. However, the LSP utilises global standards to deal with the differing regulations, such as reporting via global reporting initiative (GRI) standards. The LSP perceives itself as ahead of competitors when it comes to green performance (e.g. achieving CO₂ reduction targets). Despite its large size, the company tries to carefully manage its sustainable initiatives among its different departments. This is achieved by establishing networks driven by the topic; responsibilities are assigned in each business division and then broken down into regions and countries. However, some target conflicts between environmental management and sales departments were expressed by one participant. Achieving sustainability goals is supported by the top management’s attention on sustainability issues, where a dedicated council looks onto the overarching sustainability agenda of the company and reports directly to its top executives to ensure compliance.

4.2.3. LSPIII

This Swedish LSP offers warehousing and value-added services. Its CEO expressed a general ‘lack of interest’ from customers in demanding green solutions, especially when higher costs are associated. But few customers (often large and global ones, the ones within the B2C sector, or the ones operating in fast-moving consumer goods) emphasise green topics, and competition to satisfy this segment is expected to rise in the future. Although this LSP is ahead of environmental policies, being abreast with regulatory activities is part of its strategy, as expressed by the head of CR. He further explained that regulators’ focus is pointed towards the company due to its large size, making compliance an unescapable matter. The LSP’s green ambition is driven by a strong owner’s commitment to protect the environment while proactively exceeding legal requirements and market demands. As a result, a number of green warehousing practices are implemented, such as attaining an ISO 14001 certificate, harnessing renewable energies in buildings, enabling automatic on/off lighting in facilities and deploying waste recycling programmes. According to the CEO, two factors are seen as enablers for such applications: ‘common sense’ (i.e. human behaviour to preserve the environment) and ‘financial muscles’ (i.e. financial capacity to invest in green projects). It was expressed that the absence of transportation among its service offerings makes environmental compliance easier to attain due to: (i) the limited environmental risks in the warehousing industry compared with transportation and (ii) the narrowed managerial focus on resources and assets that are confined within the facilities’ boundaries. However, the LSP’s organisational complex structure makes it ‘difficult’ to follow up on sustainability measures and ensure their penetration across the organisation, as expressed by the COO.

4.2.4. LSPIV

This Swedish LSP specialises in providing local transportation services for heavy industries. Environmental protection is embedded in its corporate brand and core values; it strives to distinguish itself from competitors by operating trucks that run by renewable fuels (e.g. hydrotreated vegetable oil – HVO). Its strong green top managerial focus drove the company to move beyond customers’ requests by proactively offering solutions exceeding them. Large customers and the ones operating in industries with tangible environmental impact (e.g. paper industry) are often the ones prioritising green criteria when outsourcing to this LSP, whereas customers associated with low-value products (e.g. limestone industry) are seen as less green-demanding due to tight competition in their business segment. Regulatory pressure seems to play only a minor role in motivating this LSP’s green engagement, as it perceives itself ‘way above’ the local policies.

4.2.5. LSPV

This Swedish small-sized LSP offers warehousing and transportation services. Its green engagement is mainly driven by customers’ pressure, though only a few of them demand green services. These are described as the large companies that have a ‘bigger responsibility towards society’ and ‘produce a large carbon footprint’. Although this LSP is relatively small with limited resources, it still considers itself to be doing better than what the regulations in Sweden require. Competition does not appear to motivate its green engagement, due to the prevalence of price competitiveness in the logistics market. The generally low environmental pressure seems to position this LSP in a reactive role where it satisfactorily responds to policies and customer demands. Nevertheless, its slight managerial focus on sustainability led to implementing a number of internal environmental measures such as calculating CO₂ emissions and switching lights off in warehouses. But these measures are seen as somewhat costly due to the additional human effort and time needed for following up with them.

4.3. Cross-case representation of findings

This section presents cross-case information to enable synthesising our empirical findings and displaying them in a systematic manner. The analysis of the findings will be carried out in the discussion section.

Table 5 presents a group of characteristics outlined by shippers/LSPs about their logistics partners who tend to emphasise green concerns in their interactions. We used these characteristics to provide further validation and support for the influence of the pressures and moderators experienced by each actor on demanding/offering green logistics.

Table 5. Characteristics of shippers/LSPs who emphasise green concerns.

Shippers	Characteristics of LSPs	LSPs	Characteristics of shippers
SI	Large, global, possessing popular brands, operating in environmentally aware countries	LSPI	Large, listed in stock exchange, B2C sector, strong consumer brands, multinational, high environmental impact in production and end products, exceeding financial targets, operating in environmentally aware countries (e.g. Nordic countries)
SII	Large, multinational	LSPII	Large, possessing a strong sustainability vision, B2C sector, close to end consumers
SIII	Unspecified	LSPIII	Large, global, fast-moving consumer goods, B2C sector
		LSPIV	Large, high environmental impacts in production, governmental sector
		LSPV	Large, big responsibility towards society, large carbon footprint in production

Figure 2 shows a chart that links each of the shipper cases with the studied factors, along with the supporting evidence provided by LSPs. First, the three pressure sources are assessed for each of the cases while distinguishing whether these pressures are related to GSCM practices in general and/or purchasing green logistics in particular. We assessed the pressures based on their timeliness and effectiveness, and categorised them as follows:

• Current + effective (C + E): the company feels a current pressure, and responds to it through its activities.

• Emergent + effective (E + E): the company anticipates that a pressure will emerge, and initiates preparations in response.

• Current + ineffective (C + I): the company acknowledges a pressure, but does not view it as sufficient in affecting its activities.

• Absent + ineffective (A + I): the company does not feel a pressure (this also includes when a pressure is emergent but ineffective in driving the company's activities).

  Table A3 in Appendix provides direct quotes from the interviews that justify the chosen category for each shipper case.

Figure 2. Linking institutional pressures and pressure/response moderators for shippers.

Evidence related to each factor under the pressure/response moderators is checked for each case, while also differentiating between GSCM in general (code: E) and purchasing green logistics in particular (code: EP). To explain, if the participants recognised an influence of a certain moderator in engaging in GSCM practices without highlighting its role in moderating green logistics purchasing behaviour, the code E will be given. Whereas, the code EP is given if the participants explicitly emphasised green logistics purchasing in relation to the moderator. Supporting evidence of LSPs’ perceptions on green demanding shippers is given the code: SEP. As an outcome, shippers engage in GSCM practices, which includes purchasing green logistics. Examples of these for each shipper case can be found in Table A5 in Appendix.

We followed a similar approach for the LSPs’ chart (Figure 3): the three pressure sources were assessed in driving the LSPs’ green logistics engagement (see Table A4 in Appendix), and evidence for the pressure/response moderators in the cases was checked. The outcome here is green logistics practices, and examples of these are provided in Table A6 in Appendix.

Figure 3. Linking institutional pressures and pressure/response moderators for LSPs.

5. Discussion

This section provides a cross-case analysis of the cases of shippers and LSPs while reflecting on the established theoretical framework. We aim to analyse the pressures, pressure moderators and response moderator for (i) shippers to engage in GSCM practices and eventually purchase green logistics services and (ii) LSPs to engage in green logistics practices. Accordingly, a comparison between the two actors is established based on their different roles, which is later summarised in Table 6.

Table 6. Comparison between shippers and LSPs.

Pressures	Shippers	LSPs
Regulatory	Environmental policies mainly concern shippers’ own business practices, with little emphasis on handling and outsourcing their logistics functions.	Environmental policies do not seem prevalent in driving LSPs to engage in green logistics (i.e. policies are perceived as relaxed even in environmentally conscious countries).
Market	Customer demands represent a main driver for engaging in GSCM practices, but these demands mainly concern shippers’ industry-specific issues such as end products, with no focus on green logistics activities.	Customer demands form the main driver for LSPs to engage in green logistics practices, though only few shippers place high demands, and these are described in a number of characteristics (Table 5).
Competitive	Competing via engaging in GSCM practices seems to drive some shippers to differentiate themselves over the long term, with no evident link to green logistics purchasing.	Competition does not represent a major driver for LSPs to engage in green practices today (except when dealing with large and global shippers); instead, it appears to be a driver that emerges over the long term.
Firm and market characteristics (pressure moderators), comprises:
Industry	Operating in industries associated with high environmental impact from operational processes or end products could increase the pressures on shippers to engage in GSCM practices -- leading them to compensate for such impact through green logistics purchasing.	LSPs that offer transportation activities in their service packages seem to experience stronger environmental pressures than warehousing LSPs due to the evidently higher environmental impact associated with the transport sector.
Operating country	Operating in environmentally conscious countries (e.g. Sweden, Germany) could increase the pressures (especially regulatory and market) on shippers to engage in GSCM practices and possibly to purchase green logistics services.	Operating in environmentally conscious countries (e.g. Nordic region) could increase the pressures (especially regulatory and market) on LSPs to engage in green logistics practices.
Visibility	The closer the shipper is to the end consumer, the more pressure it might experience to engage in GSCM practices and possibly to purchase green logistics services.	The closer the LSP is to the end consumer, the higher the market pressure exerted on it to engage in green logistics practices.
Internationalisation	Operating internationally seems to increase the pressures on shippers to engage in GSCM practices and possibly to purchase green logistics services (due to increased stakeholders’ expectations).	LSPs operating internationally seem exposed to stronger pressures than their local rivals, as environmental demands increase across various geographical regions due to increased diversification of regulatory and market demands.
Size	Large shippers seem to experience stronger pressures to engage in GSCM and green logistics purchasing practices due to their exposure to increased public scrutiny.	Large LSPs seem exposed to stronger pressure to engage in green logistics,⁠ through two scenarios: (i) large size in terms of market share indicates a large customer portfolio and thus more diversified demands to be fulfilled and (ii) large size in terms of assets and number of employees exposes LSPs to greater public scrutiny and political demands.
Managerial commitment (response moderator), influenced by:
Interpretation of pressures	A managerial view of the environmental issues on hand as opportunities to increase profitability rather than as threats could explain the shippers’ increased engagement in GSCM practices. Shippers seem reluctant to purchase green logistics services when no direct relationship is acknowledged between cost savings and environmental performance.	A managerial view of the environmental issues on hand as opportunities to increase profitability rather than as threats could explain the LSPs’ proactivity in conducting green initiatives exceeding the imposed regulations and customer demands.
Top management support	Top management support for green topics seems to motivate managers to engage in GSCM practices, though such influence is not necessarily linked to green logistics purchasing.	Top management support for green topics seems to motivate managers to engage in green logistics practices (related to a belief in protecting the environment while simultaneously increasing profitibaility).
Economic conditions	Shippers that experience a healthy economic condition appear more likely to engage in GSCM practices and also to purchase green logistics services. Shippers that experience a tough economic condition (e.g. too high competition in their segment) appear less likely to engage in GSCM practices exceeding the policies enforced on them and accordingly less likely to purchase green logistics services.	When an environmentally ambitious LSP is financially capable of investing in green projects, it tends to demonstrate a high green engagement over the long run. LSPs generally experience a high competition and low profit margins in their segment, thus investing in green projects often requires shippers' contractual commitment.
Organisational structure	Large shippers could face more difficulties aligning their departments on green targets while purchasing logistics services due to their complex organisational structure and potentiality of conflicting internal objectives.	Large LSPs could face more difficulties ensuring the penetration of environmental strategies from top management across all divisions due to their complex organisational structures and potentiality of conflicting objectives between their departments.
Collaboration opportunities	Large shippers seem to enjoy a wide access to collaborative projects with external stakeholders, thus expanding their opportunities to engage in GSCM/green logistics purchasing practices.	Large LSPs seem to enjoy a wide access to collaborative projects with external stakeholders, thus expanding their opportunities to partake in more green logistics initiatives.

5.1. Institutional pressures

5.1.1. Regulatory

Shippers: our findings indicate that environmental policies affecting shippers mainly concern their own business practices and internal activities, whereas little emphasis is placed on how they should handle and outsource their logistics functions. For instance, logistical environmental policies were described as ‘loose’ (SII) and ‘not strict enough’ (SIII), and all the shippers expressed that tougher regulations would motivate them to put higher green demands on LSPs. This implies that shippers’ engagement in green logistics purchasing activities does not appear directly driven by regulations, as these mainly concern industry-specific functions. Such findings complement Zhu, Sarkis, and Lai (2013), who stress that institutional pressures drive firms to mainly adopt internal GSCM practices, and not external ones.

LSPs: although regulatory pressures seem to form a driver for LSPs to engage in green logistics, all the studied LSPs (large and small ones) indicated that they are ahead of the imposed policies (globally and locally), creating a sort of ‘comfortable situation’. This is surprising in two ways: first, the business units within the studied LSPs are located in countries with relatively high focus on environmental issues (Sweden, Germany), and if the regulations in such countries are not tough enough to push LSPs to go greener, then perhaps a general lack of global initiatives is the case. Second, the findings challenge many studies that consider regulatory pressures as a ‘key’ driver for LSPs’ green engagement (e.g. Lieb and Lieb 2010; Lin and Ho 2011; Rossi et al. 2013), especially in countries taking the lead on environmental change. However, the case might be that the studied LSPs are already aware of the governmental concerns on environmental topics, and thus moved from a reactive role towards a proactive one by taking initiatives surpassing the imposed policies.

5.1.2. Market

Shippers: customers’ green demands represent a main driver for SI and SII to engage in GSCM practices. Similar to regulatory pressure, most of these demands are industry-specific and not logistics-related. For example, SII expressed how its customers’ green demands relate to its end-product design due to the high energy consumption of telecom equipment. Absence of logistical focus within market pressure was also seen with SIII, where its customers (e.g. supermarket chains) prioritise cost and speed of delivery with no attention to environmental matters. This could relate to the lack of regulatory pressures on shippers concerning logistics functions, as firms often demand their suppliers to comply with the environmental policies applicable in their specific fields (Seuring and Müller 2008).

LSPs: unlike regulatory pressure, market pressure (i.e. shippers’ demands) seems to play a key role in motivating LSPs’ green logistics engagement, thus confirming previous literature (Evangelista 2014; Lieb and Lieb 2010; Rossi et al. 2013; Wolf and Seuring 2010). However, the findings from LSPs suggest that only few shippers (characterised in Table 5) put strong pressure on green requirements. But these, according to the LSPs’ viewpoint, are also the large ones who often contribute to the majority of LSPs' revenues. This appears to drive LSPs to offer green solutions to attract/satisfy these large buyers as a way increase profitability.

5.1.3. Competitive

Shippers: competing via offering green products and solutions was found to potentially drive SI to differentiate itself over the long term only, whilst not representing a competitive edge to secure business deals today. However, competition did not form a driving force for neither SII nor SIII to engage in GSCM practices. Also, it was not found to drive any of the study’s shippers to purchase green logistics from LSPs.

LSPs: all the studied LSPs (except for LSPIV) expressed that competing with their rivals is mainly based on price and service levels and not environmental issues (except when dealing with large shippers, as seen with e.g. LSPI). Yet, and as seen with LSPI and LSPIII, a trend of ‘green competitiveness’ is growing over the long term (in line with Colicchia et al. 2013), aiming to attract environmentally conscious shippers. The lack of high competitive pressure on LSPs was attributed to one of two reason: (i) a lack of green interest by many shippers (expressed by LSPI, LSPIII and LSPV), or (ii) perceiving oneself ahead of competitors (expressed by LSPII and LSPIV). Shippers’ pressure on low prices appears to shift the LSPs’ focus away from green competition, especially due to their limited capacity to invest in green projects – given the tight profit margins in the logistics industry.

5.2. Pressure moderators (firm and market characteristics)

5.2.1. Industry

Shippers: the three shipper companies in our sample belong to three different industries. These companies described the pressures on them to engage in GSCM in relation to their industries as follows: (i) SI (mining and material technology) expressed increased pressures due to the large environmental impact of its production processes, (ii) SII (telecommunication equipment) expressed increased pressure due to the high energy consumption of its end products, and (iii) SIII (food and snacks) expressed increased pressures due to the high sensitivity of its end products. Linking increased pressure to large environmental impact is supported by LSPI, LSPIV and LSPV when describing their environmentally conscious shippers (Table 5), and is in line with previous literature (Gardberg and Fombrun 2006; Hoffman 2001). Whilst linking increased pressures to energy consumption of end products is supported by LSPI and LSPV. Spotting supporting evidence from LSPs might suggest that when shippers cause large environmental impact (via operations or end products), they not only receive increased pressure to mitigate their impact but also tend to react by finding ways to compensate such impact through green logistics purchasing. The weak link between GSCM and green logistics purchasing found with SIII may be because of the nature of the food industry: although highly scrutinised, does not necessarily entail a large environmental impact, hence a feeling to compensate through buying green logistics does not seem as crucial.

LSPs: in general, the logistics industry is portrayed as an environmentally detrimental industry due to its association with high pollution and emissions, placing LSPs under strong pressure by external stakeholders. However, the pressures on LSPs diverge based on their different product portfolios: LSPs offering transportation services (e.g. LSPI, LSPII, LSPIV and LSPV) seem to witness stronger pressures than LSPs not offering them (e.g. LSP III, which offers warehousing and value-added services). This is not surprising, as among logistics activities, only 9–10% of the overall emissions are emitted from logistics warehouses, whereas the rest come from transportation activities (McKinnon et al. 2015).

5.2.2. Operating country

Shippers: in line with previous literature (Delmas 2002; Yalabik and Fairchild 2011), the cases suggest that operating in environmentally aware regions (e.g. Sweden and Germany) might increase the regulatory and market pressures to engage in GSCM practices, and possibly, to engage in green logistics purchasing practices. For instance, SIII demands trucks with certain Euro standards from LSPs just to comply with the imposed German regulations. Similarly, SI’s green logistics purchasing decisions are stimulated by the Swedish national targets to achieve fossil-free transportation by 2030. Such a notion is further supported by LSPI, who asserted that Nordic shippers demand green logistics services more than U.S. and Asian ones do, which could be attributed to the higher pressures they experience in the first place. In contrast, all the studied shippers expressed some sort of leeway within green logistics obligations in countries with relatively less environmental focus, such as Eastern European countries.

LSPs: our findings confirm that the region where an LSP operates influences the level of pressures exerted on it, as noted by the global LSPI and LSPII. For instance, LSPI’s participants expressed that its environmental development pace differs across the various geographical markets where it operates due to diversified policies and market demands (as explained above). For the other local LSPs in the sample, such as LSPIII and LSPIV, operating from Sweden is found to influence their green engagement in conjunction with the Swedish governmental focus on environmental issues. Yet, regulations on green logistics were portrayed as soft and easy to fulfil – calling for more regulatory intervention in this area.

5.2.3. Visibility

Shippers: comparing the two B2B shippers in our sample: SI expressed that the bottom line (cost and service levels) occupies its customers’ top priority, whereas green measures are minimally considered. In contrast, SII explained how its customers put quite high emphasis on green measures. This difference might relate to their varying proximities to end users. To explain, SII’s customers are telecom operators (B2C) who request specific measures to enhance their green image among their end consumers (mobile phone users). Whereas, SI’s customers operate in heavy B2B segments (e.g. machining, oil and gas) that are quite far from the end user, where a need to enhance their green image did not seem as vital. These findings could further elaborate the common argument in the literature: B2C actors are exposed to more pressures than B2B ones (Delmas and Toffel 2004; Gardberg and Fombrun 2006; González-Benito and González-Benito 2006). That is, it seems that even among B2B actors, the level of pressure may vary in proportion to proximities to end users, in which the closer the business is to the end user, the more pressure it might experience to engage in GSCM practices. Although it was not found in the shippers’ cases how these pressures are linked to green logistics purchasing, the way LSPI, LSPII and LSPIII described their environmentally conscious shippers provides a possible connection (Table 5). For instance, LSPII expressed that shippers with direct contact with end users (e.g. e-commerce firms) purchase green services to have green labels placed on the parcels delivered to their recipients, whereas B2B shippers who operate far from end users tend to purchase green services ‘selectively’. However, exceptions to this were found: Shipper III (B2B/B2C) was neither influenced by its business customers (supermarket chains) nor end consumers (buyers of snacks) to purchase green logistics, which might be attributed to the relatively low environmental risks associated with the food industry.

LSPs: although most of the LSPs in the sample operate in mainly B2B contexts, it was found that LSPs who possess popular brands (LSPI, LSPII and LSPIII; supported by SI) were subject to relatively strong pressures due to their susceptibility to increased public criticism. In addition, and similar to shippers, the cases (e.g. LSPII) indicate that the closer the LSP is to the end user the more pressure it receives from its customers (as explained above).

5.2.4. Internationalisation

Shippers: the two global shippers in our sample (SI, SII) demonstrated caution and attendance to environmental topics in an international prospect. For example, SII expressed a global sense of responsibility towards environmental logistics issues, leading it to react by implementing certain global measures such as utilising rail networks across Asia and reducing reliance on air shipments in its cross-border deliveries. The role of internationalisation in increasing environmental sustainability pressures is endorsed by the literature (Levy and Rothenberg 2002; Zyglidopoulos 2002), and its linkage to purchasing green logistics is supported by LSPI and LSPIII (Table 5).

LSPs: as found with the global LSPs in the sample (LSPI and LSPII), operating internationally seems to expose them to increased pressures, because they are expected to comply with all market and regulatory demands in each country they operate in. This applies the views of Zyglidopoulos (2002) and Levy and Rothenberg (2002) on the contract logistics literature. Coincidentally, global LSPs are also the ones at the forefront in proposing green initiatives (supported by SI, SII; Lieb and Lieb 2010), and these ones in our sample expressed a feeling of ‘comfort’ in complying with the present policies. For instance, LSPII perceives itself ‘beyond what every government is demanding’. Nevertheless, internationalisation seems to pose a difficulty for LSPs due to the lack of unified global standards imposed by regulators and shippers, which highlights a need for facilitating more standardised initiatives such as the GRI standard.

5.2.5. Size

Shippers: two of the large shippers in our sample (SI, SII) expressed relatively increasing pressures on them to engage in GSCM practices. This might relate to their prominence and large market share, which could lead to high exposure to public criticism, as explained by Arvidsson (2010) and Delmas and Toffel (2004). In addition, and according to all the LSPs in the study (Table 5), large shippers are found at the forefront in demanding green logistics services, which may be a result of strong pressures they experienced originally.

LSPs: in line with Kudla and Klaas-Wissing (2012), large LSPs experience more pressures to act responsibly than small and medium-sized ones, and this was evident in the cases through two scenarios: (i) large size in terms of market share indicates a large customer portfolio and thus more diversified demands that need to be fulfilled (expressed by LSPI and LSPII), and (ii) large size in terms of assets and number of employees exposes LSPs to more scrutiny, which leads to greater public attention (expressed by LSPIII; supported by SI and SII). These two scenarios complement the notion of Zhu and Sarkis (2007) that regulatory and market pressures typically influence large firms.

5.3. Response moderator (managerial commitment)

Based on our theoretical framework (section 2.3), managerial commitment moderates the environmental responsiveness of a firm, whereas such commitment is influenced by mainly five factors. Each of these factors is analysed in relation to our findings next.

5.3.1. Interpretation of pressures

Shippers: according to Sharma (2000), perceiving environmental issues as opportunities increases a firm’s adoption of environmental strategies, whereas viewing them as threats decreases it. In this study, both SI and SII expressed that engaging in green actions could lead to enhanced profitability, leading them to incorporate GSCM practices in their portfolio in an attempt to attract customers over the long run. However, all the studied shippers perceived green logistics solutions as costly. For instance, SIII views green issues as a ‘luxury’ that does not help the business case. This attitude has caused its lack of engagement in requesting green logistics. For SI and SII, a direct relationship between cost savings and environmental performance when purchasing logistics from LSPs was not clearly acknowledged, resulting in a reluctance to engage further in green logistics purchasing practices.

LSPs: four out of five LSPs in the sample view green strategies as a way to increase profitability over the long run due to the anticipated rise in green demands in the future. Those are also found to demonstrate further engagement and proactivity in green logistics practices. LSPV, in contrast, views green initiatives as a burden with additional costs, which might explain its limited engagement. Sharma (2000) denotes that legitimacy of environmental issues increases the chance of viewing environmental issues as opportunities. All the participants within the approached LSPs showed sensitivity to the detrimental nature of logistics activities to the environment, implying their consideration of environmental issues legitimate. This could explain LSPs’ proactivity to implement green initiatives beyond the imposed policies and customer demands, as observed with some LSPs in the sample (e.g. LSPIII and LSPIV).

5.3.2. Top management support

Shippers: SI and SII experience a strong top managerial focus on green topics, which was also reflected by both companies’ core values. This, as conveyed by the interviewed managers, created a motivational atmosphere for their green engagement, as they strived to align their performance and decisions with top management’s ambitions. Such findings conform with previous literature (Ahmad et al. 2016; Zhu, Sarkis, and Geng 2005). In contrast, and in line with Hillary (2004), lack of top management support appears to clearly demotivate managers within SIII to engage in green initiatives, as the focus was solely on cost reduction strategies. However, even when the support is there, it does not seem necessarily related to purchasing green logistics; no emphasis on green logistics was detected on neither of SI’s or SII’s values and strategies, nor was that emphasised by the participants’ input.

LSPs: similar to shippers, the influence of top management support was evident by all the LSP cases. However, evidence from LSPI, LSPII, LSPIII and LSPIV shows that top management demonstrates such awareness not only to protect the environment, but also due to a belief that such engagement would attract more customers and increase profitability.

5.3.3. Economic conditions

Shippers: the tough economic situation experienced by SIII due to high competition in its segment has shifted the company’s focus from green measures to cost-cutting strategies, which resulted in adopting a strictly reactive approach by minimally complying with the imposed policies to maintain its license and avoid penalties. This scene complements the argument of Campbell (2007), who asserts that too high (or too low) a level of competition decreases the chance of responsible behaviour, which also seems to explain SIII’s lack of interest in requesting green logistics from LSPs. In contrast, SI expressed a willingness to pay more for green logistics solutions, which might indicate a healthy financial situation. Such a notion was further supported by LSPI, asserting that shippers that are outperforming financially tend to request green logistics services.

LSPs: our empirical analysis indicates that when an environmentally conscious LSP is financially capable of investing in green projects, it tends to demonstrate a high green engagement over the long term (e.g. LSPIII and LSPIV). However, this is not the common scene, because most LSPs face low profit margins due to the competitive nature of the logistics industry, where investing in green projects (e.g. an intermodal transport system) without customers’ commitment over a reasonable period of time appears problematic. In the end, LSPs follow what customers demand and their engagement is essential to trigger green endeavours (Wolf and Seuring 2010). This situation illustrates the abovementioned argument of Campbell (2007) on the contract logistics literature as well.

5.3.4. Organisational structure

Shippers: the participants within SI and SIII indicated how their large and complex organisations led to conflicting environmental objectives between their departments, which in turn hindered their GSCM practices and particularly their green logistics purchasing measures. For instance, SI’s green logistics purchasing initiatives were hindered due to target misalignment between the four departments concerned with logistics outsourcing (sales, freight, finance, production), where each seems to have different priorities (e.g. sales: lead time, freight: consolidation of goods).

LSPs: our findings confirm the argument of Kudla and Klaas-Wissing (2012): large LSPs face more difficulties ensuring the penetration of environmental strategies from top management across all divisions, which was found with LSPII and LSPIII due to their intricate organisational structures and potentially conflicting objectives between their departments. Though, LSPII’s top management strives to counter-act this by assigning sustainability responsibilities in each business division and then breaking them down into regions and countries.

5.3.5. Collaboration opportunities

Shippers: the global shippers in the sample (SI and SII) engage in green logistics projects with different actors (e.g. rail operators, LSPs, consultants, authorities, R&D facilities), thus encouraging their green logistics purchasing behaviour. This conveys the academic view of the influence of collaboration opportunities on green logistics decisions for LSPs (Kudla and Klaas-Wissing 2012; Lieb and Lieb 2010) to shipper organisations as well.

LSPs: the role of collaboration opportunities in influencing managerial commitment seems evident with three large LSPs in the sample (LSP I, LSPII and LSPIII): they seem to enjoy better access to collaborative projects with government authorities, manufacturers, schools, R&D facilities, etc., which provides them with more opportunities to partake in green initiatives compared to smaller LSPs (in line with Lieb and Lieb 2010).

5.4. Comparison of the pressures and moderators between shippers and LSPs

To fulfil the third research purpose, we compare the influence of institutional pressures and pressure/response moderators between shippers and LSPs (summarised in Table 6).

In general, regulatory, market and competitive pressures on shippers are mainly directed towards their business functions with little emphasis on green logistics purchasing practices. In turn, regulatory pressure does not seem prevalent in driving LSPs’ green decisions; evidence indicates that LSPs feel comfortable in that area. In contrast, market pressure seems to be the main driver for LSPs’ green logistics initiatives, though only few shippers demand them (described in Table 5). These shippers, although few in number, seem to contribute to the majority of the LSPs’ revenues (according to the LSPs’ viewpoint). Competing via offering green solutions helps LSPs to secure the deal for those particular shippers, but in general, competition is rather perceived as a driver emerging over the long-term horizon.

In terms of industry, shippers that operate in industries associated with high environmental impacts through their operational processes or end products appear to be exposed to strong pressure on GSCM practices, which seems to stimulate them to compensate via green logistics purchasing practices. Correspondingly, LSPs that offer transportation services in their service packages are typically exposed to stronger pressures compared to those not offering it (e.g. warehousing companies) due to the evident environmental harm of transportation activities. Shippers and LSPs alike are exposed to higher pressures (particularly regulatory and market) to implement GSCM practices (including green logistics) in environmentally aware regions in comparison to other regions with less environmental awareness. For visibility, the cases indicate that the closer the business is to the end user, the more pressure it perceives to implement GSCM practices, and particularly to purchase/provide green logistics services. Operating internationally also increases the pressure on shippers and LSPs to engage in GSCM actions such as buying/providing green logistics, since they are expected to comply with stakeholders’ expectation in every country where they operate. The cases show that particularly large shippers and LSPs experience strong pressures to engage in sustainability actions due to their dominance in the market and their high exposure to public criticism, whereby the insights from LSPs strongly suggest that large shippers are at the forefront in requesting green logistics services from LSPs.

Our analysis indicate that a managerial view of environmental issues as opportunities to increase profitability rather than as potential threats could explain: (i) the shippers’ increased engagement in GSCM practices and (ii) the LSPs’ proactivity in conducting green initiatives beyond the imposed regulations and shippers' demands. On the other hand, viewing green topics as burden costs with high risks could diminish green proactivity for both actors. Top management support is seen as a vital factor in stimulating managers within both types of actors to demonstrate further green engagements. However, shippers that experience a tough economic situation appear less likely to engage in GSCM practices exceeding policies enforced on them, and accordingly, less likely to purchase green logistics services. Therefore, because the level of competition is relatively high in the logistics industry, for LSPs to invest in green projects requires a willingness from shippers to engage in green endeavours through the established contractual agreements. In contrast, enjoying a healthy economic condition helps shippers to invest jointly in green logistics projects with LSPs (or pay extra for green services) and helps LSPs invest in long-term green logistics projects. A complex organisational structure of large shippers and LSPs could be challenging for their green logistics decisions in two possible scenarios: (i) aligning departments on environmental targets while purchasing/offering green logistics and (ii) ensuring the penetration of environmental strategies from top management across all divisions. Though, large shippers and LSPs seem to gain wider access to collaborative projects with public and private actors compared to small ones, thus expanding their opportunities to engage in GSCM practices as well as purchasing/providing green logistics services.

6. Conclusions

This study analysed the institutional pressures that stimulate the environmental engagement of two actors within supply chains: shippers (logistics buyers) and logistics services providers. After investigating the GSCM and the contract logistics bodies of literature, a gap was observed in identifying whether what stimulates shippers to engage in GSCM practices is directly linked to demanding green logistics services from LSPs. Moreover, acknowledging to what degree shippers’ demands motivate LSPs to implement green logistics practices seems underexplored, especially in consideration of the influence of other external actors, such as regulators and competitors. Accordingly, we applied institutional theory to analyse what stimulates both actors’ green engagement along three pressure sources: regulatory, market and competitive, in accordance with previous GSCM literature (Colicchia et al. 2013; Zhu and Sarkis 2007). Through the established theoretical framework, a number of firm and market characteristics influencing the level of pressure on companies to engage in environmental practices were identified and illustrated from different academic viewpoints. These were referred to as ‘pressure moderators’, and they comprise: industry, operating country, visibility, internationalisation and size. By the same logic, managerial commitment moderates the environmental responsiveness of companies, and such commitment is influenced by the factors: interpretation of pressures, top management support, economic conditions, organisational structure and collaboration opportunities. Analysing these pressures and moderators outlined how they influence shippers to engage in GSCM practices (and particularly purchase green logistics), and LSPs to provide green logistics services.

The empirical evidence was obtained from a multiple-case study comprising three shippers and five LSPs. Each of the pressures, pressure moderators and response moderator were empirically analysed and cross-matched with the theory, resulting in formulating a comparison between the influence of the pressures and moderators based on the actors’ different roles in the supply chain (Table 6).

This study contributes to institutional theory by providing further applications in GSCM and contract logistics contexts. Specifically, it explains how the three pressure sources (regulatory, market, competitive) influence the two key actors in the supply chain that are mainly responsible for facilitating green logistics practices. Further, it extends the investigation of institutional pressures by incorporating the pressure/response moderators, which aids in understanding the influence of specific firm and market characteristics in moderating the level of pressures, and managerial commitment in moderating the environmental responsiveness. In addition, application of the developed framework (Figure 1) is not necessarily confined to a contract logistics context; it can also be applied to other industries within the broader scope of the GSCM literature.

This study assists practitioners within shipper and LSP firms via demonstrating what stimulates them in buying or providing green logistics services, while taking the influence of regulators and competitors into consideration. Particularly for shippers, this article provides insights into how their institutionalised settings influence their GSCM strategies, while distinguishing between internal decisions and logistics purchasing ones. For LSPs, this study highlights the prevalence of market pressure in comparison to the other two sources, while further distinguishing between shippers that emphasise green measures and those that do not (Table 5). Understanding this would help LSPs with marketing strategies; they could modify their green proposals based on the characteristics of the shippers.

One of the main limitations of this study is that empirical data were obtained from a relatively few number of cases with a limited number of industries, and that all the cases are located in either Sweden or Germany. Even for the covered industries, generalisation cannot be claimed, as each shipper industry is represented by one case only. Bearing this in mind, the empirical part of this paper should be seen as elaborative for the established theoretical framework. Accordingly, testing the findings through a survey in a wider geographical and industrial extent is recommended for further research.

Acknowledgements

We would like to thank all the interviewed participants for sharing their valuable insights. We further thank professor Lars Bengtsson for his support throughout the project, as well as our colleagues and the two reviewers who helped in refining the work. Our thanks extend to Jennie Johansson, Emma Wiklund and Johan Eriksson for their assistance in the data collection process.

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Appendix

Table A1. Summary of pressures and moderators for shippers engaging in GSCM practices/green logistics purchasing.

Pressures	SI	SII	SIII
Regulatory	Focus on plant and production processes Little emphasis on logistics functions More policies are requested on green logistics	Main focus on core business ‘Loose’ policies on green logistics The company is ahead of logistics legislations curve in most countries where it operates More policies are requested on green logistics.	Tough regulations on food production processes and facilities ‘Not strict enough’ policies on green logistics activities Green logistics compliance is only on basic levels requested by government More policies are requested on green logistics
Market	Main focus on production processes Customers expected to increase sustainability demands in the future Little attention to green logistics	Main focus on product design due to high energy consumption Little/no attention to green logistics	Main focus on food production (in line with regulations) No attention to green logistics from customers (priority to ship goods as soon as possible regardless of environmental impact)
Competitive	Green measures within product portfolio assist in securing future deals Purchasing of green logistics is not driven by competition	No role in driving GSCM practices Purchasing of green logistics is not driven by competition	No role in driving GSCM practices Purchasing of green logistics is not driven by competition
Pressure moderators, comprises:
Industry	High environmental impacts within steel and mining industry increase the pressure due to public criticism	High energy usage of telecom products increases the demands for environmental measures	Operating in the food industry increases sustainability demands due to high sensitivity and scrutiny
Operating country	Swedish plants are exposed to relatively strong pressure due to political and market green focus in Sweden Green logistics purchasing is stimulated by Swedish national fossil-free transport target Low green logistics demands in Eastern/Southern European countries	Some countries (e.g. Sweden in particular and Europe in general) have tougher regulations than others	Tough environmental demands on food plants in Germany German laws mandate specific Euro-class trucks Low(er) green logistics demands in Eastern⁠ European countries
Visibility	Cost and service levels occupy the highest priorities for its B2B customers Customers operate in B2B segments, and are quite distant from end users	Customers operate closely to end users Customers are putting green demands to satisfy their end users	N/A
Internationalisation	Caution on environmental issues is expressed in a global sense	Caution on environmental issues is expressed in a global sense	N/A
Size	Company’s large size increases the pressure due to popularity and public scrutiny	Company’s large size increases the pressure due to popularity and public scrutiny	N/A
Response moderator (managerial commitment), influenced by:
Managerial interpretation	Sustainable development is seen as an opportunity over the long run Green logistics solutions perceived as costly alternatives A direct relationship between cost savings and environmental performance is unrecognised	Sustainable development is seen as an opportunity over the long run Green logistics solutions perceived as costly alternatives A direct relationship between cost savings and environmental performance is unrecognised	Green logistics solutions are perceived as costly alternatives Sustainability is perceived as a ‘luxury issue’ Green alternatives are only chosen if cost savings objectives are fulfilled
Top management support	Strong top managerial focus to preserve the environment	Strong top management focus to preserve the environment	Lack of top managerial focus on green issues
Economic conditions	Willing to pay more for green logistics to achieve environmental targets	N/A	An unstable economic condition due to extremely high competition in the market shifted the focus away from green logistics purchasing
Organisational structure	Conflicting objectives between departments when purchasing green logistics	N/A	Purchasing freight services is handled by procurement department (rather than supply chain dept.), where the focus is solely on cost reductions rather than quality of services
Collaboration opportunities	Participation in green transport workshops with relevant actors (e.g. LSPs, consultants, regulators) supported green logistics purchasing behaviour	Collaborative green projects are conducted with different organisations (e.g. network operators, maritime companies, infrastructure, rail operators, R&D facilities)	N/A

Table A2. Summary of pressures and moderators for LSPs to engage in green logistics practices.

Pressures	LSPI	LSPII	LSPIII	LSPIV		LSPV
Regulatory	‘Soft’ environmental regulations Not a central driver LSP is ahead of current policies ‘Political touch’ hinders effective regulations	Occupies a secondary rank for driving green actions LSP is ahead of current policies (a ‘comfortable situation’)	LSP is ahead of imposed regulations Abreast with regulatory activities	Represents a minor driver for green engagement LSP is ahead of current Swedish policies		Although a small LSP, it perceives itself ahead of imposed Swedish regulations
Market	Main driver for green engagement Triggers proactivity Demanding shippers: minority in number, majority in revenues	Main driver for green engagement Demanding shippers willing to pay extra for green offerings Few shippers demand green logistics B2Bs demand green logistics ‘selectively’	General lack of customer interest in green offerings Few customers demand green services Market demands expected to rise in the future	Represents a moderate driver for green engagement Few shippers demand green services		Main driver for green engagement Few customers demand green services
Competitive	Main competition is on price and service levels Forms a moderate driver for green engagement Green portfolio secures deals for green-aware shippers Green competition expected to increase in the future	Main competition is on price and service levels Perceived itself ahead of competitors in green engagement Green portfolio secures deals for green-aware shippers	Main competition is on price and service levels Sustainable commitment is gradually becoming a competitive advantage (long term)	Main competition is on price and service levels LSP strives to distinguish itself through green offerings Going green does not compromise price competitiveness Perceives itself ahead of competitors		Main competition is on price and service levels Not a driver for green engagement
Pressure moderators, comprises:
Industry	Operating in logistics increases pressure due to high environmental risks	Operating in logistics increases pressure due to high environmental risks	Absence of transportation in services minimises pressures		High emissions from transportation increase pressures	Operating in logistics increases pressure due to high environmental risks
Operating country	Nordic customers are more demanding than U.S. and Asian ones	Some countries have tougher policies than others The LSP sees itself beyond what every government is demanding	Operating in Sweden influences green engagement due to high political focus		Operating in Sweden influences green engagement due to high interest in the region	N/A
Visibility	Operating in B2B and B2C led to extra pressures Possessing a popular brand increases pressures	Pressure increases in with increased proximity to end users Possessing a popular brand increases pressures	Possessing a popular brand increases pressures		N/A	N/A
Internationalisation	Global perspective is taken while handling environmental issues in logistics	Global perspective is taken while handling environmental issues in logistics Extra efforts to comply with diverse regulatory and shipper demands	N/A		N/A	N/A
Size	Large customer portfolio increases pressure Large number of employees increases regulatory attention	Large customer portfolio increases pressure Large number of employees increases regulatory attention	Large number of employees increases regulatory attention		N/A	N/A
Response moderator (managerial commitment), influenced by:
Interpretation of pressures	Environmental issues seen as opportunities Green engagement increases profitability over the long run Environmental issues are legitimate	Environmental issues seen as opportunities Green engagement increases profitability over the long run Dedicated board to handle green issues Environmental issues are legitimate	Environmental issues seen as opportunities Green engagement increases profitability over the long run Some green measures could reduce costs Environmental issues are legitimate		Environmental issues seen as opportunities Environmental awareness embedded in core values Proactivity in innovating solutions that exceed market/regulatory demands Environmental issues are legitimate	Green alternatives perceived as costly due to increased tasks and human efforts Environmental issues are legitimate Mainly reactive
Top management support	Top management focus on environment	Top management focus on environment	Top management focus on environment		Top management focus on environment	Moderate managerial focus on sustainability
Economic conditions	Tough competition in the logistics market due to low profit margin Green investments’ mainly rely on customer demands and commitment	Tough competition in the logistics market due to low profit margin Green investments suffer from short contract periods	Tough competition in the logistics market due to low profit margin Ability to conduct long-term green investments		No extra cost associated with investing in biofuel trucks	Tough competition in the logistics market due to low profit margin Green investments suffer from short contract periods
Organisational structure	N/A	Attempts to be ‘in shape’ in managing sustainability goals between depts. Conflicts arise due to complex organisational structure (between sales and environmental units)	Insuring penetration of sustainability strategies across the company is difficult		N/A	N/A
Collaboration opportunities	Engagement is influenced by access to collaborative projects with government departments, manufacturers, R&D facilities, etc.	Engagement is influenced by access to collaborative projects with consultants, regulators, etc.	Engagement is influenced by access to collaborative projects with schools, R&D facilities, etc.		N/A	N/A

Table A3. Examples for pressures on shippers.

Pressure	Case	Viewed as …	Example quotations from participants
Regulatory
On GSCM practices in general	SI	Current + effective	‘Yes of course. For example, Länsstyrelsen, they demand us to comply with certain operational standards (…) We have some instructions in the steel industry, and there comes the environmental demands.’ (SI-II) ‘If the government is setting up a target, then it will be a real thing. Let’s say, if the European committee said that we’re going to reduce CO2 emissions by 20% in 2020, this will have an effect on us, I think that is one of the triggers to start this.’ (SI-I)
	SII	Current + effective	‘I think at some point in time we’ve said we want to be CO2 neutral. We are mandated by the law actually. In our yearly report we publish our carbon footprint and so on. And there is pressure that those figures should be improved.’ (SII-I)
	SIII	Current + effective	‘One part of course is to cope with legal responsibilities. In Germany we have some legal requirements. Since we work in the food industry there are quite some laws that we have to obey. We need to obtain some sort of sustainability certificate (…) and there’s an audit conducted every year on that.’ (SIII-I)
On purchasing green logistics in particular	SI	Current + ineffective	‘But, the demands for logistics are not so tough. What the government has said so far is that “you should calculate and measure”, and this is not enough to have a real change. They can put more taxes on CO2 emissions for example!’ (SI-II) ‘If the government puts more pressure and tax on it [green logistics purchasing], then of course this will help.’ (SI-II)
	SII	Current + ineffective	‘Up until now the regulations have been rather “loose” and I think in most countries we have been ahead of the curve; we have met regulatory requirements when it comes to logistics functions. And I think the authorities could probably put more pressure here.’ (SII-I)
	SIII	Current + ineffective	‘From the government’s side, in terms of logistics, we don’t really have any regulations. Of course there are certain types of trucks we have to use, and they need to be of specific type of Euro class. But this is for everyone in Germany, otherwise the trucks are not allowed to operate.’ (SIII-I) ‘I think another barrier is that the rules from the legislators are not strict enough. Of course if the government puts on stricter rules, then we would have to comply.’ (SIII-I) ‘No there is no real pressure from the government or something like that. Not now at least.’ (SIII-II)
Market
On GSCM practices in general	SI	Current + effective	‘Our main customers are in the oil and gas industry and in the automotive industry, so of course we are creating indirect pollution. What we need is to work more in reducing as much pollution and emissions as possible for everyone.’ (SI-I) ‘The main driver is, of course, what we see coming more and more from our customers. Their wishes and demands imply that we must be better in the environmental sustainability area.’ (SI-II)
	SII	Current + effective	‘Most companies want to hook up with the sustainability trends. I think the pressure that customers put on us is on the product itself (…) The radio base station equipment that we produce consumes quite a lot of energy because of its technology, and therefore we try to produce every new generation with much more power efficiency.’ (SII-I) ‘We have quite a number of customers to whom we actually built and set up solar power stations. So it makes a huge imprint in what we sell. We definitely see a pickup in this area, and it’s slightly increasing in the coming years. Because the business case is there.’ (SII-I)
	SIII	Absent + ineffective	‘From my perspective, it [environmental awareness] is only for marketing purposes to be put it in the website. In the end our customers want to buy our product for the low price, and they’re not really interested in whether it is really green.’ (SIII-II) ‘We don’t see pressure from the end-customer. When they choose which salty snacks to buy it’s not a motivation for them to buy the product because of some sustainability label on the package. If that would change I’m sure that would be a driver.’ (SIII-I)
On purchasing green logistics in particular	SI	Emergent + effective	‘When we sell our products, it [green logistics] could be “an extra” that helps us to get the new business. But I won’t say it’s a strong pressure, at least not from many customers today.’ (SI-II) ‘The business is not there yet. Since we’re B2B, I still think the bottom line is more interesting for our customers, but environmental concerns will come more and more, and some customers will start pushing us soon in that area’ (SI-II)
	SII	Absent + ineffective	‘I think the pressure that customers put on us is on the product itself, and not on how we handle our warehousing and transportation activities.’ (SII-I)
	SIII	Absent + ineffective	‘No. Currently, from the customer side, I’m talking the supermarket chains here, they want to have high delivery rates, so this is what they focus on. They don’t really care about how we do it.’ (SIII-I) ‘No. We in the transport department didn’t notice pressure from the customer side. We don’t notice requests regarding CO2 calculations for example.’ (SIII-II)
Competitive
On GSCM practices in general	SI	Emergent + effective	‘An interesting thing is that more and more of our competitors are putting the environmental criteria higher on their agenda. So it will soon be part of our sales offer too.’ (SI-II)
	SII	Absent + ineffective	‘I can’t say we’ve reached a time where competition is about environmental performance. I don’t think this is the case.’ (SII-II)
	SIII	Absent + ineffective	‘We state in our website that we are environmentally friendly, but that’s only for marketing, in reality we don’t really care about it.’ (SIII-II)
On purchasing green logistics in particular	SI	Absent + ineffective	‘When I discuss with other big companies like us about green transportation, I see nothing much happening there to be honest.’ (SI-II)
	SII	Absent + ineffective	‘I wouldn’t say the environmental issue is on top of the agenda today when we select our LSPs, then I’d lie (…) When I talk to the industry, most companies are acting in a similar way as us, they think it’s important, but when they choose a global LSP it’s not the number one concern. There are other factors that are considered more important.’ (SII-I)
	SIII	Absent + ineffective	‘There is no other competitors who do it [purchasing green logistics], and I don’t think there would be any pressure for us in that sense.’ (SIII-II)

Table A4. Examples for pressures on LSPs.

Pressure	Case	Viewed as …	Example quotations from participants
Regulatory
To engage in green logistics	LSPI	Current + ineffective	‘We need to have policy-makers, with rules and regulations, pushing the transformation process. That’s the baseline and it’s very important and vital in pushing the industry to improve.’ (LSPI-III) ‘I think the regulations are too soft. We have been waiting for, for instance, regulations limiting CO2 emissions for so long (…) They say that there will be taxes on travelled km and on CO2 emissions, and there will be penalties on air emissions within cities and things like that … but, no.’ (LSPI-II)
	LSPII	Current + ineffective	‘There’s a lot of what governments can do. Specially with going green now the case is often that we’re beyond what every government is requesting. So this is rather a comfortable situation for us.’ (LSPII-I)
	LSPIII	Emergent + effective	‘The regulators are aware of the problem, they are of course doing things. But I don’t think they’re doing the right thing to be honest. They should push us to use technology more and improve efficiencies.’ (LSPIII-I) ‘There is one obvious driver, and that is we’re a large company and there’s a law in Sweden right now that started last year. That you have to have a report on the plan, and how you work with CSR’ (LSPIII-III)
	LSPIV	Current + ineffective	‘We are way above the requirements that are put by the government. (…) I’m missing more regulations.’ (LSPIV-I) ‘Well, so far the government has not done so much for changing to sustainable fuels. (…) Today we have 18 years where we should have fossil-free transport in Sweden, and that’s a short time. I think they have to do more to reach that target.’ (LSPIV-I)
	LSPV	Current + ineffective	‘I think the pressure from the government is low. The only way we see it is through taxes, the fuel prices are getting higher, and that could influence us (…) And that’s the only way we see or hear anything from the government regarding that.’ (LSPV-I) ‘We’re not very engaged because we don’t receive enough pressure from the government. Maybe if we have more pressure we’d do it, but since we don’t it’s easier to consume energy more than we should.’ (LSPV-II) ‘No they [policies] are not really tough. I’d say we’re either on the margin, or above. For example, if somebody comes from the government saying “I want to check your trucks and everything”, we wouldn’t be panicking.’ (LSPV-II)
Market
To engage in green logistics	LSPI	Current + effective	‘Mainly the customer. If the customer is willing to reduce its carbon footprint, we will contribute and take part as a response to customer’s demand.’ (LSPI-IV) ‘If you look at our company globally, the big global accounts we have stand for around 20% of the total turnover, and many of them, not all of them, but many, have sustainability demands and requests.’ (LSPI-I) ‘You do have customer segments where you have customers on the market, buyers of transport and logistics services, that are actually more likely to do business with a transport company that has a higher profile on sustainability. However, that’s actually not huge, but it exists there for sure.’ (LSPI-III) ‘I’d say that the initiative many times comes from the transport buyer.’ (LSPI-II)
	LSPII	Current + effective	‘I’d say overall the demands for green solutions are pretty much driven by our business customers.’ (LSPII-I) ‘So one thing is that a lot of our customers more and more ask us to make sure that we’re fulfilling sustainability requirements. They want to make sure they’re working together with a responsible provider. Also, a part of them go even a step further and say we want to explicitly buy green solutions from you.’ (LSPII-I)
	LSPIII	Emergent + effective	‘I don’t think there is yet so much customer demands, but maybe there should be. I think that would be more and more in the future. So if you’re not there I don’t think you’ll be a supplier for the future.’ (LSPIII-I) ‘Depends on the size of the customer. So if you want to play with the big guys, as we want to do, it would be a focused part to show that we’re working on this and we have a structure and a good leading system for how to follow up with it.’ (LSPIII-II)
	LSPIV	Current + effective	‘There’s some pressure from the customers, to make the transport more environmental friendly. Those customers are normally “kommun”, or state governmental customers. They’re good on putting high demands. Still a lot of our customers focus on price of course.’ (LSPIV-I) ‘There are a lot of big companies who put environment on top ranking. Normally when we negotiate with these customers there is a sustainability chief included at the table.’ (LSPIV-I)
	LSPV	Current + effective	‘Some of them ask for it (…) I’d say bigger companies are more demanding, that’s maybe because they have a department that only works with these questions. Smaller companies don’t have such resources.’ (LSPV-I) ‘Yeah there’s a little pressure there. You’re not well seen if you don’t care about the environment. So you get better PR if you show that you care, and the customers would feel like “Well this is a company that is doing a change so I’d rather pick them instead of the ones not showing initiative”’ (LSPV-II) ‘Some customers, not all of them. Most of them just look into the prices and the services we can offer (…) But with the big customers, those having a bigger responsibility to the society, there I feel that pressure. They call us a lot and often ask us “How is this stored?” “In what conditions are these driven?”. So some customers that have higher pressure on sustainability would check more often on us.’ (LSPV-II)
Competitive
To engage in green logistics	LSPI	Emergent + effective	‘If you want to be on the list of possible suppliers to the big companies then you have to have a program for sustainability. That was one important driver.’ (LSPI-I) ‘In the competition between us with other suppliers, if we know that we have the best sustainability solutions for that customer, then there is a tendency that we will focus on it and bring it to the table and put emphasis on those things because we believe our competitors are less good in this aspect.’ (LSPI-I)
	LSPII	Current + ineffective	‘If you look at what other companies are doing, we’re probably well ahead.’ (LSPII-I)
	LSPIII	Emergent + effective	‘In the long term we’re not giving away anything (…) I’m sure that if you don’t work with this, then you’ll lose money and customers on the long term.’ (LSPIII-III) ‘I don’t think there is yet so much customer demands, but maybe there should be. But I think that would be more and more in the future. So if you’re not there I don’t think you’ll be a supplier for the future.’ (LSPIII-I)
	LSPIV	Current + ineffective	‘But there are lot of those companies who have that focus as well. And then you have to be the best in that class.’ (LSPIV-I)
	LSPV	Absent + ineffective	‘I think we are almost like the others I’d say. So no pressure from competitors. It’s about price.’ (LSPV-I)

Table A5. Examples for GSCM/green logistics purchasing practices for shippers.

	Examples of …
SI	GSCM practices in general Using flapper valve steel for improved energy efficiency Purchasing low-emission electricity in accordance with the European Guarantees of Origin scheme Obtaining environmental management system certificates (ISO 50001) in production plants Reducing energy consumption in coal power plants Using renewable energy sources (e.g. solar energy) in several production plants Using, reusing and recycling materials in production plants (e.g. using recycled steel) Reusing refractory as a slag-forming agent in steel plants Purchasing green logistics in particular Demanding trucks that meet high Euro standards (e.g. Euro 6) Requesting detailed calculations of CO2 emissions from LSPs
SII	GSCM practices in general E-waste management (gathering and recycling e-waste from telecom operators) Producing energy efficient hardware and equipment Reducing energy usage in facilities (e.g. offices, production sites, data centres) Utilising renewable energy sources (e.g. solar energy) in several production plants Demanding suppliers to control and measure their water usage Purchasing green logistics in particular Shifting from air to surface product transport Consolidating the number of locations where goods are sorted to strategically-located distribution centres
SIII	GSCM practices in general Obtaining certified energy management system (ISO 50001) in factories Reducing energy and water consumption during food production Reducing non-edible waste in production plants Supporting sustainable palm oil production through aligning policies with WWF’s recommendations Purchasing green logistics in particular Optimising packaging quality (e.g. reducing packages’ size and volume, reducing waste by fewer machine stops) Requesting a certain type of Euro class trucks that are required by German laws

Source: Interviews information and secondary data.

Table A6. Examples of green logistics practices for LSPs.

	Examples of green logistics practices
LSPI	Acquiring modern truck fleets with more efficient engines Applying eco-driving principles Shifting to most environmentally friendly transportation mode Reducing transport miles by consolidation Route and fuel optimisation Reducing energy consumption in warehouses Calculating, monitoring and controlling CO2 emissions of transport and warehousing activities
LSPII	Utilising alternative fuel engines in trucks Acquiring trucks with more energy efficient engines Investing in more efficient aircrafts Obtaining environmental management system certificates (e.g. ISO 14001, ISO 50001) in a number of warehouses Using bicycles and electrical scooters for small deliveries within cities Utilising renewable energy sources (e.g. wind, hydropower, solar, biomass) in warehouses Including green electricity/environmental energy policies in suppliers and subcontractors code of conduct Calculating, monitoring and controlling CO2 emissions of transport and warehousing activities
LSPIII	Reducing energy consumption of heating and electricity in warehouses and facilities (e.g. LED lighting, motion control, district heating systems) Utilising 100% green electricity in warehouses Adopting waste recycling programmes (e.g. sorting waste for suppliers, hiring only approved waste management actors) Monitoring and controlling energy usage in facilities Decreasing areas of landfill sites by fractioning
LSPIV	Operating 100% fossil-free truck fleets (e.g. biodiesel and HVO trucks) Obtaining environmental management system certificates (e.g. ISO 14001) Modifying trucks to operate on electrical motorways
LSPV	Calculating CO2 emissions of transport and warehousing activities Reducing energy consumption in the warehouse (e.g. LED lighting, switching lights off) Monitoring eco-driving behaviour

Source: Interviews information and secondary data.