Integrating Sector-Wide Reforms for Mitigation
A recent study in São Paulo shows that expanding road capacity by 20 percent would speed up car travel by 13 percent, which would improve vehicle fuel efficiency. But increased speeds could encourage more car use, so that fuel consumption would increase 5 percent and CO2 emissions 3 percent (Anas and Timilsina 2009b). Similarly, road expansion in the periphery of Beijing would increase private car use; improvements in city mass transit would reduce it. But because more buses could worsen city congestion, total emissions in that case would decline by only a few percent. Alternative modes alone do not guarantee emissions reduction. In principle, transport emissions, especially from cars, could be reduced by supply-side measures such as increasing alternative transport options, improving current infrastructure energy efficiency, or connecting different transport modes more effectively. Using available transport assets more effectively is just as important, especially in developing countries where a number of measures could enhance efficiency. Finally, different transport modes should be connected so that people can use them flexibly and efficiently, without taking unnecessary detours. This demands a much broader city management approach, including land-use and transport planning policies.
Supplying Alternative Transport Modes The modal structure of transport plays an important role in determining carbon emissions, particularly when car ownership is relatively low (box 3.2). Shifting from passenger vehicles to mass transit can significantly reduce emissions (table 3.5). An average public bus emits only half as much CO2 equivalent per passenger-km as a small petrol-fueled car. Railways, especially between cities that are far apart, are even more ecofriendly. Light-rail emissions are less than or at most equal to average bus emissions. Subways also seem to be less polluting, though this depends on passenger occupancy. For large vehicles, such as public buses, compressed natural gas (CNG) and liquefied petroleum gas (LPG) have an advantage over diesel (Defra 2009). Since the late 1990s, 30 major cities in China have implemented the National Clean Vehicle Action program to use more CNG and LPG for public transportation. More than 80 percent of taxis in Shanghai and 50 percent of buses in Beijing use CNG or LPG (Hou and others 2002; Zhao 2006). The relevance of particular transport modes depends on city size, density, and other geographic factors. For rapidly growing, densely populated large cities, rapid transit and light rail transit can be best. In Bangkok, for instance, an elevated 23.5-km rapid mass transit system, Skytrain, was constructed in 1999 to relieve congestion. As of 2008 the system was transporting 460,000 passengers a day (Mandri-Perrott 2010). Another mass transit system, MRT (mass rapid transit) Blue Line, that went into service in 2004 was used in 2007 by more than 170,000 customers a day. Road traffic was reduced along the Blue Line, although only marginally for several reasons (JBIC 2008). Manila’s LRT1 has been a major public transportation mode since it was commissioned in 1985. LRT1 carries about 300,000 people a day. In Tunis, the 32-kilometer LRT (Light Rail Transit), in operation since 1985, was carrying some 294,000 people per day in 2002 (Godard 2007). Turning the Right Corner • http://dx.doi.org/10.1596/978-0-8213-9835-7
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