Benefit-Cost Evaluation of Traveler Information: Seattle’s Washington State Department of Transportation Website

Abstract

The Washington State Department of Transportation website allows those with access to a computer and the Internet to obtain current information about traffic conditions on freeways and bridges in the metropolitan Seattle area. Potential benefits of disseminating real-time traveler information are time and cost savings to users as a result of informed travel choices (route, time, mode, destination, add or forgo a trip), increased user confidence in travel choices, and reduction in congestion, pollution, and other external costs. These benefits depend on how many users access the information, what choices they make, how much time they save or in what other ways they find the information valuable, and how their choices affect the transportation system. Although a good deal of this information is available for Seattle or can be estimated from comparable contexts, the data are inadequate to determine within a broad range whether net benefits are positive or negative. A spreadsheet model is presented that allows relevant data to be applied—and “what if” numbers to be inserted where necessary—as a basis for identifying the performance characteristics and levels needed to make a traveler information service a worthwhile investment.