The Estimation of Environmental Impacts for Transport Policy Assessment

Abstract

The analysis of traffic and transport alternatives by means of mathematical models is well-established as an aid to design and economic assessment. The emphasis in the past has been on the traffic effects of the policies involved, and it is only recently that methods have been devised to give approximate estimates of the levels of and degree of exposure to noise, air pollution, and pedestrian interference as an essential part of the study of traffic and transport proposals. This paper covers the design and use of special models, and the collection and analysis of noise and pollution data in a form suitable for forecasting. The application of the techniques is illustrated by means of models of Coventry drawn from the Transportation Study report. One model was designed to simulate conditions in 1967, and another to simulate extreme (and unlikely) conditions in a future where congestion and pollution are both severe. The environmental impact estimation process has been integrated into the RRLTAP transportation modelling research system. The strengths and weaknesses of this approach are brought out by an illustrative application. Special attention has been paid to the different pollution estimation equations as a basis for forecasting, and the degree to which a particular choice could affect the results.