On the Measurement and Valuation of Travel Time Variability Due to Incidents on Freeways

Abstract

Incidents on freeways frequently cause long, unanticipated delays, increasing the economic cost of travel to motorists. This paper provides a simple model for estimating the mean and variance of time lost due to incidents on freeways. It also reviews methods for assigning a monetary value to the variability that such incidents introduce into daily travel. The paper offers an easy-to-implement approach to measuring the performance of freeway incident reduction strategies, an approach that should be useful in early project selection exercises where a sketch planning process is used to identify promising actions.