Technical and economic potentials for reducing greenhouse gas emissions will vary by region according to differences in geography, existing transportation infrastructure, technological status of existing transport equipment, the intensity of vehicle use, prevailing fuel and vehicle fiscal policies, the availability of capital, and other factors. Differences in spatial structure, existing infrastructure, and cultural preferences also influence the modal structure and level of transport demand.

Many developing countries and countries with economies in transition are experiencing rapid motorization of their transport systems but are not yet locked into a road-dominated spatial structure. In addressing the transport problems of these economies, the World Bank (1996) has emphasized the importance of combining efficient pricing of road use (including external costs) with co-ordinated land use and infrastructure investment policies to promote efficient levels of transport demand and modal choice. Without providing specific GHG emission reduction estimates, the World Bank study notes that non-highway modes such as rail can reduce energy requirements by two-thirds versus automobiles and 90% versus aircraft, in situations where the modes provide competitive services.

Studies of transport mitigation options in Africa and Asia have emphasized behavioural, operational, and infrastructure measures in addition to technology. In Africa, in particular, options that have been examined include: the reduction of energy intensity through expanding mass transit systems (e.g., modal shifts from road to rail), vehicle efficiency improvement through maintenance and inspection programmes, improved traffic management, paving roads, and the installation of fuel pipelines (e.g., modal shift from road or rail to pipeline), provision of infrastructure for non-motorized transport, and decarbonization of fuels through increased use of compressed natural gas or biomass ethanol (Baguant and Teferra, 1996; Zhou, 1999). Mass movements of goods, passengers, and fuel become more cost-effective as the volumes and load factors increase, and for most African countries this is likely to be achievable only after 2010 (Zhou, 1999). In studies conducted for East and Southern Africa, these options were found to be implementable at little or no cost per tC (Table 3.12). Zhou (1999) has estimated that investments in paving roads, rail freight systems and pipelines could reduce greenhouse gas emissions in Botswana at negative cost (Table 3.12). Vehicle inspection programmes, as well as fuel decarbonization by use of compressed natural gas and biomass ethanol were all estimated to be no cost to low-cost options. Bose (1999a) notes that in developing countries mass transport modes and demand management strategies are an essential complement to technological solutions because of three factors: (1) lack of leverage in global vehicle markets to influence the development of appropriate transport technologies; (2) the relatively greater importance of older, more polluting vehicles combined with slower stock turnover; and (3) the inability to keep pace with rapid motorization in the provision of infrastructure.

Table 3.12: Estimated costs of greenhouse gas mitigation options in Southern Africa (Zhou, 1999; UNEP/Southern Centre, 1993).
Measure	Cost (US$/tC)
Paved roads	–41.42
Road freight to rail	–31.47
Petroleum and product pipelines	–18.91
Fuel pricing policies	0.00
Vehicle inspections	0.20
Rail electrification	111.94
Compressed natural gas	1.37
Ethanol	–186.5

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