Transport Planning and Environmental Assessment: Implications of Induced Travel Effects

Figures & data

Figure 1 Induced travel.

Figure 2 Induced travel during period of underlying growth in demand.

Figure 3 Relationship between travel time and land values with distance from activities.

Table 1. Policy measures listed in GOMMMS.

Land-use measures

Concentration of development in corridors or at transport nodes

Mixing development so that destinations are closer

Higher density development

Parking standards

Company travel plans to reduce commute trips

Flexible or staggered work hours

Developer payments

Telecommunications such as telecommuting

Infrastructure measures

New road construction and expansion of existing roads

New car-parking facilities

New conventional rail

Light-rail system development

Guided buses

Park-and-ride lots

Terminal and interchanges to coordinate services

Cycle routes and lanes

Pedestrianized zones

Lorry parks for overnight parking

Intermodal trans-shipment facilities

Encouragement of other freight modes (rail, water, pipelines)

Management measures

Conventional traffic management (e.g., one-way streets, junction redesign, parking controls)

Urban traffic control systems

Intelligent transport systems

Accident blackspot remedial measures

Traffic restraint measures including traffic calming

Regulatory restrictions on car usage

Parking controls

Car sharing (or encouragement of carpooling)

Bus priority lanes

High-occupancy vehicle lanes

Increased public transport service

Bus service management measures

Improved pedestrian crossings

Cycle parking

Lorry routes and bans

Information provision

Conventional direction signage, including for lorry routes

Variable message signs

Real-time driver information and route guidance

Parking guidance and information systems

Public awareness campaigns on environmental issues related to car usage

Public transport timetable and service information

Real-time public transport information provision

Information for management of public transport fleets

Fleet management systems for freight

Pricing measures

Parking charges

Workplace parking charges

Urban and interurban road charging, especially congestion charging

Public transport fare changes and structural changes

Concessionary public transport fares (e.g., disabled and elderly)

Table 2. Recommended elasticity values for calculating induced travel effects.

	Travel time elasticity
Peak period
Urban areas with high modal competition	−0.33
Urban areas with low modal competition	−0.20
Interurban	−0.20
Peak hour
Urban areas with high modal competition	−0.55
Urban areas with low modal competition	−0.33
Interurban	−0.33
Off-peak
Urban areas with high modal competition	−0.40
Urban areas with low modal competition	−0.24
Interurban	−0.24

Table 3. Appraisal summary table.

Option		Description	Problems	Present value cost to government (£m)
Objective	Subobjective	Qualitative impacts	Quantitative measure	Assessment
Environment	Noise			Net properties win/lose with scheme
	Local air quality			Concentrations weighted for exposure
	Greenhouse gases			Metric tons of CO2
	Landscape			Score
	Townscape			Score
	Heritage of historic resources			Score
	Biodiversity			Score
	Water environment			Score
	Physical fitness			Score
	Journey ambience			Score
Safety	Accidents			PVB £m
	Security			Score
Economy	Transport economic efficiency			Users: NPV £m Private providers: NPV £m Public providers: NPV £m Other government: NPV £m
	Reliability			Score
	Wider economic impacts			Score
Accessibility	Option values			Score
	Severance			Score
	Access to the transport system			Score
Integration	Transport interchange			Score
	Land-use policy			Score
	Other government policies			Score

Highways Agency . 1997 . Design Manual for Roads and Bridges, Volume 12, Section 2, Part 2: Induced Traffic Appraisal .

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