Trade-offs between time, cost, and uncertainty by commuters in hyderabad, India - Stated preference survey assessment

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 trade-offs 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.