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In developing countries, air quality assessments that include the transportation sector have tended to focus predominantly on assessing technological solutions to problems associated with vehicle pollutant emissions, energy consumption, and greenhouse gases. This focus can be justified on the basis of the favorable cost-effectiveness, political acceptance, and ease of quantifying technological measures—at least in the short term—but unfortunately it often leads to the exclusion of demand-oriented measures. Further, air quality and pollution policy analysts often use assumptions of exogenously determined travel demand patterns, implicitly excluding many opportunities to look at policies oriented toward travel demand as an air pollution control strategy. The air quality impacts of policy measures to influence vehicle kilometers traveled and mode shares, such as bus rapid transit, are investigated. The approach involves developing coefficients with a stated preference (SP) survey that could be used to test policies with a conventional four-step urban transportation model. The main purpose of the SP survey in this study was to examine traveler tradeoffs among time, cost, and reliability (measured as uncertainty in vehicle departure time). Some different methods of measuring reliability were tested during the pilot phase of the survey, as were the actual range of parameter values to be tested. Models were estimated using traveler cohorts based on levels of vehicle ownership. In comparing vehicle owners (cars and two-wheelers) with nonowners, owners were found to be substantially more sensitive to time and reliability while nonowners were more sensitive to price. All groups showed notable sensitivity to reliability. Policy implications of these results are discussed, with a notable conclusion being that demand-oriented measures appear to be a fruitful area for further investigation as air pollution control strategies, even when technological measures show strong effectiveness.

Many developing-country cities are experiencing severe air quality problems as a result of rapidly increasing vehicle use and highly polluting vehicles. Yet, data availability and modeling capabilities to support travel and emissions forecasting in developing countries are limited. One result is that policies that affect travel demand cannot be properly evaluated or are overlooked as solutions to air quality problems. Exploratory research to determine the need for and feasibility of developing a “sketch plan” travel forecasting method that can be applied in developing-country cities is described. Outreach to practitioners and researchers was undertaken to identify the extent of existing transportation data availability and forecasting capabilities. The research revealed a broad range of capabilities. Less-developed countries—including most countries in Africa and some in Asia and Latin America—often have no formalized forecasting approach, little data (which may be of suspect quality), and no institutional structure to support data collection or forecasting. Some of the more developed countries—especially in Southeast Asia and Latin America—have capabilities approaching or equal to those of western countries. The results suggest that, in many developing countries, there is a need for as well as interest in a simple tool for forecasting travel demand that minimizes data inputs and user requirements. Existing sketch-plan methods used in developed countries were also reviewed for potential application to developing countries. Because of significant differences between developed- and developing-country contexts and issues, however, a tool appropriate for developing-country cities probably would need to be developed from scratch.