ABSTRACT
This chapter explains how traffic forecasts are made, suggests some principles for formulating transport plans, and shows how alternative plans are evaluated. The overall aim of the transport planning process is to advise policy-makers on the alternatives available, the trade-offs involved, the resources required and the likely benefits. The chapter provides an elementary introduction to techniques for forecasting population, employment and car ownership at the aggregate urban scale, the zonal scale and the disaggregate household scale. The distribution of household types within zones is required both for category analysis and for any examination of the distributional or equity implications of alternative plans. The chapter explains how travel demand forecasts are calculated from changes in future land-use activity. It discusses assumptions underlying these traffic forecasts and their likely accuracy. The chapter suggests some principles to follow when formulating transport plans, and outlines methods used in the economic, social and environmental appraisal of alternative plans.
