Using Bus Rapid Transit to Mitigate Emissions of CO₂ from Transport

Abstract

This article investigates the role of bus rapid transit as a tool for mitigation of transport‐related carbon dioxide (CO₂) emissions. We analyse a Quality Bus Corridor (QBC) implemented in Dublin, Ireland, in 1999 and estimate CO₂ emissions associated with differing levels of bus priority for the period 1998–2003 and for the Kyoto commitment period (2008–12). Associated monetary values are established using CO₂ prices from the European Union Emissions Trading Scheme. We find that, in the absence of a QBC, peak‐time emissions for our sample population would have been 50% higher than in the factual scenario. For the Kyoto commitment period, we find the median value of the policy implementation to be in the region of [euro]650 000.

Notes

1. Here EBLs are defined as one lane in each direction of a road reserved exclusively for buses, other public transport (i.e. taxis) and emergency vehicles. Danaher et al. (forthcoming) described BRT as ‘an integrated system of facilities, equipment, services and amenities that improves the speed, reliability and identity of bus transit. BRT is, in many respects, rubber‐tired LRT with greater operating flexibility and potentially lower costs. It must be noted that bus priority as it operates in Dublin should be regarded as a modest application of BRT, especially compared to examples in Latin America, for more see Levinson et al. (2003a)’.

2. The treaty, signed by more than 165 countries and ratified in February 2005, commits to a 5% reduction on 1990 levels by 2008–12 (http://unfccc.int/essential_background/kyoto_protocol/status_of_ratification/items/2613.php). The EU ratified the treaty in May 2001 and committed to an 8% reduction over the same period. Ireland is committed to restrict such emissions to 13% above 1990 levels.

3. This is a reversal of traditional scenario construction methodology for BRT and, more generally, cost benefit analysis (which typically focus on ex‐ante analysis of future projects).

4. In 2004, the QBC under investigation was extended along the N11 Road to the county boundary (a further 5.4 km). As a result, subsequent data may be confounded with the effect of this extension. Our projections for the years 2004–12 do not deal directly with this extension.

5. Murray et al. (1998) and Murray (2001) have suggested a catchment area of 400 m from each bus stop for bus travel, but after consultation with Dublin Bus and the DTO, it was decided that a 400 m limit was too conservative for a bus priority scheme and that 800 m more closely represented the catchment area. The model used by the DTO assumes a 10 min walking distance (800 m) is a typical distance for QBC commuters (at a walking speed of 5 km/hr).

6. If not stated otherwise, the term ‘trip’ in this article refers to a one‐way trip along the N11 QBC to or from the Central Business District.

7. Miles were converted into kilometres using a factor of 1.609 km per mile. We adjusted for slight presentational changes between the two censuses and selected the midpoint of each category presented to respondents. Those who said that they travelled less than 1 mile and those who did not state the distance of their commute were excluded.

8. Each profile contained the status quo bus journey and two between 32 possible hypothetical alternatives (each profile was constructed orthogonally). The seven attributes presented to the respondents are peak journey times, off‐peak journey times, bus stop waiting facilities, seat availability, real‐time information at bus stops, ticket machines at bus stops and cost. There is, of course, some debate as to the relative merits of stated preference surveys relative to revealed preference data. However, given that we are discussing future projections and that the authors administered the survey as per the present state of practice in the field (i.e. see Hensher and Greene, 2003), we hope that such concerns should be mitigated somewhat.

9. Mayer and Davies (2004) noted that the typical fuel consumption of a diesel bus of a similar type of city bus to our average bus is 50 L per 100 km and 1 L of diesel fuel has an energy content of 10.8 kWh. This translates as an energy content of 5.4 kWh/km.

10. The Dublin Bus network is a radial network and the number of routes that do not cross the cordon area count is very small.

11. Recent reports suggest that the voluntary agreement levels will not be met (http://environment.guardian.co.uk/travel/story/0,,1997422,00.html).

12. That is in 2008, network vehicle kilometre by Dublin Bus is 58 125 704.57 (assuming a linear relationship from the figures in MVA, 2006). Maintaining the proportion of peak kilometre at 49.52% results in 28 783 848.9 peak kilometre. Maintaining the share of total kilometres accounted for by the N11 at 11.65%, results in bus vehicle kilometres on the N11 of 3 353 036.09 km. Allowing for an increase in the share of total kilometres in line with the modal shift, results in the share rising to 13.353% and N11 peak bus vehicle kilometres increases to 3 843 585.27 km.

13. 129.47% of 11.65% is 15.082%.

14. Recorded in the week of 21 January 2005 and the week of 21 April 2006, respectively. All price data come from the Carbon Market Europe Weekly Newsletter (Point Carbon, 2006).

15. Scott Wilson (2000) estimated the cost at IR£200 000–400 000 per km, we assume the higher band of this estimate is accurate and apply the standard Euro conversion rate of 1.2697 = IR£1. Inflation as measured by the consumer price index (CPI) has grown by 20.80% between 2000 and end of 2004 (http://www.cso.ie/releasespublications/documents/prices/current/cpi.pdf).