This section identifies and categorizes mitigation strategies, discusses potential constraints on their effective implementation, and describes relevant policies and financial mechanisms.
Mitigation strategies
The transport sector represents around 30 percent of global CO2 emissions, with urban transportation comprising more than half of this amount. This is the type of greenhouse gas emissions "that is expected to grow the fastest in business-as-usual scenarios, increasing at an annual rate of 2-3 percent" (Zegras, 2007, p. 112). The largest part of this growth is expected to happen in developing countries. Price et al. (2006, p. 122) forecast a worldwide average annual growth rate between "2.2 and 3.4 percent over the next 30 years.4 During this 30 year period, the share of developing countries, in world transportation co2 emissions, is projected to grow substantially (Price et al. , 2006). However, developing countries account for about five times the population of the developed countries. Thus, per capita urban transportation emissions in developing countries remain many folds lower than developed country cities. The aim of mitigation strategies is to reduce the transport carbon footprint of the city. Because of the complex interrelationships between transport, land use and climate change, reducing greenhouse gas emissions requires a two-pronged approach to tackle urban energy consumption, combining both transportation policy and land use policy. Linkages with other sectoral policies also are critical.For transportation, motorized vehicles can be made more efficient, carbon content of fuels reduced, use of private vehicles discouraged, and efficient non-motorized and public transport promoted. For land use, urban planning and land use regulation, property taxes need to be adapted to facilitate the concentration of private investment in areas of high accessibility, generated by the implementation of mass transport systems. This will reduce the need for mobility due to higher density and diversity of urban functions. Non-motorized commuting can also be encouraged through appropriate urban design and the articulation of different types of transportation. Table 6.3 shows strategies for reducing greenhouse gas emissions in urban transportation systems, through a combination of demand and supply management policies in transportation systems and land use policies.
Table 6.3: Mitigation strategies for urban transportation systems and related land use.
|
Demand |
Supply |
|
|
Transport |
Transport demand management; speed |
Investment in mass transit system. |
|
limits; congestion pricing; fuel tax; public transport subsidy; promotion of non-motorized transportation; road tolls; parking fees; provision of eco-driving schemes. |
Regulation and incentives for improvement of vehicle energy yields or low emission fuels. Facilitate inter-modal linkages application of information technology. |
|
|
Land use |
Land use planning; provision of basic services; property tax regimes to discourage sprawl. |
Zoning regulation; town planning schemes; incentives for high density urbanization, regulation to discourage sprawl. |
Regulatory instruments are applied in various forms; for instance, limiting the number of days a vehicle can be on the road, as is the case in Beijing, Bogota, and Mexico City’s "hoy no circula" (one day a week, without a car) or quantitative restrictions on ownership, as in Singapore. However, unintended market distortions from such interventions require attention (for details see Bertaud et al., 2009). Efficient fuels and technology choices are alternate mechanisms to reduce CO2 emissions. For instance, compressed natural gas (CNG) operated automobiles emit between 20 and 30 percent less CO2 than automobiles operating on a regular gasoline engine (Ministry of Environment, Government of Japan, 2008). In this regard, over the five-year period from 1998 to 2002, in Delhi all public transport buses were converted to CNG operated systems largely due to a verdict by the Supreme Court of India.Moreover, the Delhi Metro Rail Corporation introduced measures to reduce greenhouse gas emissions through the use of regenerative braking to capture the energy during deceleration and feed it back into the electrical system. Delhi Metro Rail is considered the first railroad company to obtain carbon credits through such an effort.
Pricing instruments (Table 6.4) modify consumer incentives; for instance, relative prices between private vehicles such as cars and mass-transit modes such as commuter rails. Cities around the world deploy different types of pricing instruments – fixed tolls and congestion pricing as in the case of Singapore, London, and Stockholm; fuel tax as in Bogota, Singapore, Chicago; parking charges as in New York, Sheffield, Edinburgh (Bertaud et al., 2009). Some of these pricing efforts aim to reduce market distortions. Pricing congestion and parking, for instance, aims at adjusting the price of using a highway or of a parking space to reflect its economic value, including externalities due to congestion.
Pricing instruments also include subsidies. Subsidies are often aimed at redistribution. For instance, many transit fares are subsidized, as in Los Angeles, San Francisco, Mumbai, Delhi. Transit fare subsidies are aimed at increasing the mobility of low-income households, allowing them to fully participate in a unified metropolitan labor market. Transit fare subsidies are also an incentive for car commuters to opt for a modal switch to transit. Although, this is not a very effective manner to increase transit mode share in the long run (Bertaud et al., 2009).
Table 6.4: Environmental benefits of congestion pricing.
|
City |
Environmental benefits, including decline in carbon dioxide emission (per year) |
Source |
|
London (2002-2003) |
Within the congestion pricing zone: 19.5% carbon dioxide emission reduced; 12% decline in oxides of nitrogen; 12% reduction of suspended particulate matter (PM10, particles <10 micrometers in diameter; 15% drop in vehicle kilometers travelled. |
Beevers and Carslaw (2005) |
|
12% decrease in traffic |
Transport for London (2004) |
|
|
2.3-2.5 million pounds in savings from carbon dioxide emission reduction; decline of 211-237 million vehicular miles travelled |
Evans (2007) |
|
|
Reduction of 35% in pollution; total environmental benefits: €4.9 million |
Prud’homme and Bocarejo (2005) |
|
|
Stockholm (January-July 2006) |
13% carbon dioxide emission reduced (or 36,000 tons in saved emissions); 8.5% decline in oxides of nitrogen; 14% drop in carbon monoxide levels;13% reduction of PM10; avoidance of 27 premature deaths; 22% reduction of vehicle passages in congestion pricing zone. |
Johansson et al. (2008), Lundqvist (2008) |
|
Singapore (1998, 1992, 1975) |
75% reduction of car traffic during morning peak hours; in 1992 car volume was 54% of the pre-1975 level; in modal split, share of cars dropped from 48% to 29% immediately congestion pricing was introduced. |
Olszewski (2007) |
|
1998: Elasticity of passenger cars -0.106 within congestion pricing zone (-0.21 in the short run, -0.30 in the long run); 15% drop in daily traffic volumes. |
Olszewski and Xie (2005), Olszewski (2007), Menon (2000) |
|
|
1975: Traffic volumes in morning peaks reduced by 45%; car entries decreased by 70% |
Willoughby (2000) |
|
|
Milan (2008) |
9% carbon dioxide emission reduction (or 150,000 tons per year reduced); 19% reduction of PM10-emissions; savings of €3.3 million; 37% decline in ammonia (NH3) emissions; 11% drop in oxides of nitrogen emissions; traffic reduced by 14.4% |
Milan municipality (2009) |
|
Durham |
Number of vehicles declined by 50-80% |
Santos and Fraser (2005) |
Pay-As-You-Drive (PAYD) programs offer another mechanism to reduce vehicular miles traveled. With encouragement from public authorities, insurance companies are charging insurance premiums based on driving records and other traditional risk factors but are broken down into per-mile charges. Motorists have the opportunity to lower their insurance costs by driving less. When PAYD insurance is offered to a large percentage of California drivers, it may reduce vehicle miles traveled and associated greenhouse gas emissions (Lefevre and Renard, 2009). Such strategies have limited application in a developing country city context, where car ownership is limited to a small fraction of urban households and most trips are by walking, bicycling, and other two wheelers, complemented by severely constrained mass transit systems. Instead, Perera and Permana (2009) present alternate strategies appropriate for developing countries using the case of Bandung City, Indonesia.
Bicycling is also being encouraged in developed country cities with the aim of reducing automobile dependency and associated greenhouse gas emissions. Strategies take the form of bicycle rental stations, being used in a number of European cities, and provision of bike lanes. On the other hand, while non-motorized transport accounts for a large proportion of commuter trips within the developing country city, the challenge with rising incomes is to facilitate the retention of such low emissions modes as well as complement with demand-responsive mass transit, as opposed to the present trend of low-cost motorized personal transport. Curitiba in Brazil has been a noteworthy example of the use of bus rapid transit in South America, though examples are now widespread throughout the world from Mexico City to recent efforts in Delhi. Shaping land use is also another way to improve accessibility while mitigating emissions; however, the degree of public control on land use varies significantly by jurisdictions and its efficacy remains debatable.
On categorizing energy consumption in urban transport in developing countries by the degree of land use planning: (1) controlled residential and commercial areas, (2) unplanned peri-urban areas, (3) planned satellite towns, Permana et al. (2008) find that, in Bandung City, Indonesia, households in "controlled residential and commercial areas" use transport systems -including walking and bicycling – that consume less energy than households in unplanned or planned areas. However, there are several confounding covariates, such as income and type of employment, which correlate with the type of land use (a proxy for house prices) and modal choices, that need to be analyzed further for relevance in alternate geographies.
New York City’s mitigation efforts in transportation largely center on some key initiatives within PlaNYC (2007) and the Metropolitan Transport Authority’s (MTA, 2009) Blue Ribbon Task Force. PlaNYC and subsequent regulatory and management initiatives to support the plan’s goals, including environmental ones, emphasize anti-idling laws and parking restrictions. The city’s congestion pricing initiative did not get the support of the New York State legislature. In the area of transit, the MTA, which is the primary provider of transit in the city, has incorporated a strategy of greening its stations and supporting facilities such as maintenance yards.
Assessments of mitigation potential and cost
There are some efforts to assess urban transportation sector mitigation potential and cost, but this is still an incipient trend, based on a city-by-city analysis. There is no worldwide urban transportation sector mitigation potential and cost assessment in the literature.
Until now, the issue of cost-effectiveness has been successfully applied to international negotiations, such as the European Emissions Trading Scheme (EU-ETS), and to national policies. Energy-economy or sectoral energy models have made it possible to simulate the economic impact of different policies and especially to build sets of marginal abatement cost curves. These mechanisms are efficient tools for analyzing different aspects of climate policies, particularly seeking to reduce the global cost through a certain leveling of the marginal costs of sectoral initiatives (Lefevre and Wemaere, 2009). The development of marginal abatement cost curves for urban transportation aims to inform methodological efforts to measure and prioritize the actions to inform policymakers’ choices.
For instance, the Siemens study of London’s transport system (Siemens, 2008) estimates a reduction in transport emissions "by about one-quarter, from 12.1 million tons of CO2 in 2005 to 9 million tons in 2025". The study identifies better fuel efficiency in cars as a cost-effective means of reducing carbon emissions from transport. In addition, hybrid cars and some biofuels hold abatement potential, albeit at higher costs, given present technology. London could save 0.3 million tons of CO2 by 2025 by switching to hybrid buses and optimizing road traffic management. For similar calculations on how much becaks (human powered tricycle transport) and ojeks (motorcycle taxis) can contribute to reducing CO2 in Bandung City see Permana et al. (2008). Increased use of biofuels could cut emissions by 0.5 million tons – assuming biofuels with low greenhouse gas emissions are used.
As cities are complex, a project-based approach is insufficient to reduce urban transportation carbon emissions. Instead an incremental programmatic approach is more likely to be highly cost-effective such that local climate action plans apply a systemic approach to innovations in spatial organization and transportation planning in the broader context of city development and management. For a case study of such an incremental approach see the case of Bandung City (Perera and Permana, 2009).
Constraints to mitigation in urban transportation systems: prospects for green technology diffusion
In the near future, "emergence and large deployment of viable green individual transport technologies is limited" (Pridmore, 2002; Cabal and Gatignol, 2004; Assmann and Sieber, 2005). A study by Heywood et al. in 2003, as cited by Zegras (2007), assesses the potential for advancements in passenger vehicle technology "in the United States over a 30-year horizon and concludes that a combination of technological improvements and demand management will be required to reduce transportation energy consumption". Furthermore, according to Assmann and Sieber (2005) the additional time needed for a well-established technology in developed countries to penetrate the market in developing countries is around 10 years. Consequently, according to some estimates a new "green" car, launched today in the developed world, will take 40 to 45 years to reach a significant share of the market in poor countries (Cabal and Gatignol, 2004). However, the pace and scope of global technological diffusion remains a subject of great debate and these estimates need to be revisited as empirical data on technology transfer from developed to developing countries and vice versa becomes available for the urban transport sector.
Mitigation of urban transportation systems requires multilevel-governance arrangements – city level, regional, national, and in some cases global. For instance, while a city can ensure that all vehicles used for city operations are fuel efficient (including taxis), it requires federal legislature to set fuel economy standards and enforce compliance by automakers, as was the case in Santiago (Chile) and Bogota (Colombia). At the national scale, the U.S. has instituted Corporate Average Fuel Economy (CAFE) standards for automobile manufacturers for each model year. (NHTSA 2010). Additionally, measuring carbon emissions at the city scale is challenging for several reasons – the city’s jurisdiction does not necessarily overlap with the urban agglomeration, embedded carbon in goods consumed within the city but produced at long distances, or emissions due to transit passengers all pose accounting challenges. In the case of Bandung city, as in many other cities, land use, energy, and transportation policies lack horizontal interagency coordination and vertical intra-sector collaboration (Perera and Permana, 2009).
Public policies that accomplish greenhouse gas reduction in the urban transportation sector are challenging in part because climate change competes with other pressing priorities. Policymakers, especially those in developing countries, face the challenge of ensuring sustainable development of their transportation sector in order to meet the demands of rapid urbanization, economic growth, and global competition. The green agenda is limited to local environmental challenges, especially local air quality, a classic example being Delhi. However, co-benefits from these efforts offer positive externalities in emission reduction as well as capacity-building for institutional response to combat climate change.
Non-point sources imply diffused emission, making it difficult to collect baseline data for monitoring and evaluation of emissions and their reduction. Additionally, a life-cycle analysis is required if greenhouse gas emissions in the urban transport sector are to be fully accounted. Due to diffuse emission sources it is difficult to involve the key actors necessary to influence the level of greenhouse gas emissions for a given urban transportation system. Finally, due to lack of capacity and willingness of local institutions, enforcement is ineffective.
Mitigation policies
Policy objectives for greenhouse gas emission reductions in the urban transportation sector may include both demand-and-supply-side initiatives (see Table 6.3 for example). Demand-side interventions include reducing the need for transportation through land use planning and incentives for decreasing vehicle miles traveled. Some instruments include congestion pricing, charging user fees for parking, and fuel tax to internalize the social cost of the transport sector into pricing to correct for market distortions that presently do not price environmental degradation due to carbon emissions; incentivizing use of clean fuel vehicle technology, and the like. Supply-side interventions include enhancing the provision of energy-efficient mass-transit systems; regulating land use to preserve and enhance carbon sinks (forests, wetlands) when considering locations of new infrastructure facilities as well reducing the need for transit through better land use management; and coordinating land use and transport policies to exploit synergies (Schipper et al., 2000).
The key stakeholders for mitigation response are various levels of government, firms, and households. While the state takes the lead on supply-side initiatives, including regulation and provision of transport systems and providing incentives for behavioral change, private and public vehicle producers respond by supplying various degrees of fuel efficiency in transport modes – cars, rails, and buses. Consumers – both households and firms that consume transport services – lead demand-side initiatives, including consumer choice of transport modes and the like. However, the various levels of government, types of vehicle producers, and consumers of various transport services have a complex set of overlapping and conflicting interests. For instance, while transit-oriented local governments may create incentives for mass-transit systems, state governments with car manufacturing bases may oppose such initiatives. Likewise transit may be welcomed by non-car-dependent urban communities and resisted by car-dependent suburban communities and vice versa. The effectiveness of such mitigation instruments also varies between developed and developing countries. In many developing countries, as car ownership is limited and demand for transportation services is rapidly growing, creating incentives for fuel-efficient private and public transportation systems can yield substantial gains in reduction of the growth of greenhouse gas emissions.
Financial tools and incentives
Two key incentive mechanisms for mitigation of greenhouse gas emissions from urban transport systems are intergovernmental transfers and carbon markets. Federal transfers for management of ecological goods and services, which are public goods with positive externalities beyond local jurisdictions, are in practice. For example, since 1996, the "German advisory council on the environment has called for the integration of ecological indicators into intergovernmental fiscal transfers" and performance indicators. For instance, financing is determined partially on the basis of improvements in rural land management and protection of nature reserves (Perner and Thone, 2005). In India, the thirteenth finance commission advised that 7.5 percent of fiscal transfers to states and union territories be based on percentage of forest cover (Kumar and Managi, 2009). While these environmental grants are performance-based the scope of the projects is limited, but such federal grant conditionals can potentially include broader concerns of climate change, including urban transport mitigation, as in the case of Klimp, a Swedish investment grants scheme targeted at sub-national level governments to address climate change.
Likewise, carbon markets are underutilized for energy-efficient urban transportation. Only two out of twelve hundred clean development mechanism (CDM) projects that have been registered by the UNFCC’s Executive Board address urban transportation projects. These two projects are TransMilenio, Bogota’s bus rapid transit, and Delhi subway’s regenerative braking system.Together these two urban transport projects represent less than 0.13 percent of the total CDM project portfolio.
The underutilization of CDMs for urban transport projects is due to three key factors. First, there is a mismatch between the local expertise and global requirements. Local government priorities and associated skills are aimed at developing transport projects to ease severe mobility constraints in developing countries. In contrast, the global institutional requirements of CDMs and the associated standards and fees for screening applications and fulfilling requirements are often beyond the scope and abilities of local governments. Second, due to the diffused emissions in the transportation sector, the cost of aggregating data is high. Thus CDM’s "act and gain money" incentive has limited impact. Third, basic CDM project requirements are difficult to fulfill for urban transportation: project boundaries are difficult to define due to up- and down-stream leakages, establishing credible baselines is difficult due to constraints in data collection, and data constraints render monitoring methodologies unreliable.
Enhancing the proportion of urban transport projects within the existing CDM framework may require focusing on short gestation and high-return energy-efficient technologies – technology switch to energy-efficient engines and fuels switch; mass-transit systems; information technology for transport systems optimization, such as smart traffic light systems bundled together for programmatic CDMs. These have co-benefits for urban transportation sectors that are yet to be explored. Like the CDMs, the urban transport sector has yet to adequately utilize the Global Environment Facility (GEF), established in 1991 to support developing countries in tackling climate change mitigation and adaptation (Colombier et al., 2007). Thus, project preparation and development support remain a critical gap in linking urban transport to broader climate change and environmental initiatives. In addition to carbon markets, the Partnership on Sustainable Low Carbon Transport, among others, is exploring alternate strategies for financing low-emission urban transport systems through pooling of public and private resources as well as sector-wide approaches to low carbon transport.
