The goal of advanced traveler information systems (ATIS) is to provide travelers with information that will facilitate their decisions concerning route choice, departure time, trip delay or elimination, and mode of transportation. The benefits of ATIS projects can be evaluated through field studies, simulation software, and surveys. An evaluation method called the ITS Deployment Analysis System (IDAS) is suggested for use by the Washington State Department of Transportation (WSDOT). IDAS is a “sketch” planning tool intended for screening and prioritizing all intelligent transportation systems (ITS) projects (not just ATIS projects). The software evaluates a number of benefits. These are determined by changes attributable to the deployment of ITS in vehicle miles traveled (VMT), vehicle hours traveled (VHT), volume-capacity (v/c) ratios, and vehicle speeds throughout a given network.
The IDAS evaluation depends on a number of assumptions that affect the calculations of costs and benefits. The IDAS developers recommend that these assumptions be inspected by local agencies and adjusted to better represent local conditions. The assumptions about the impacts on VMT, VHT, v/c ratios, and vehicle speed are particularly important. Consequently, suggestions are made within this report for adjustments that WSDOT should make to these default values. These values will allow the WSDOT to successfully employ IDAS for ATIS evaluation.