The authors document an initial attempt to ascertain the potential benefits of a real-time in-vehicle traffic information system under recurring and nonrecurring congestion conditions. An actual network in the Santa Monica freeway corridor in Los Angeles was simulated via the FREQ8PC and TRANSYT-7F models. Travel times for both freeway and surface street links from these models were transformed to a network model called PATHNET, which was utilized to determine the travel times for the shortest path between any origin and destination point or for any other path in the network desired. The shortest path is assumed to be the perfect information path. Also considered were freeway-biased paths, arterial-biased paths, and user-defined paths. Comparisons were made for a set of four origin points and three destination points. Under the recurring, non-incident congestion scenario the travel time savings when utilizing the shortest path were generally negligible (less than three minutes for a 20-25 minute trip). Under the nonrecurring, incident congestion scenario (where the incident was created on the freeway and assuming that a small percentage of drivers divert to the surface streets), travel time savings were found to be significant.
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