California Partners for Advanced Transportation Technology

It has often been assumed that travel time savings are only beneficial to the users of route guidance and navigation systems. In particular, absolute travel time savings have been emphasized, but there has been little interest in relative time savings between equipped and unequipped vehicles. Part 2 of this report investigates to what extent relative travel time savings decrease as the percentage of equipped vehicles increases.

In order to compensate for a possible decrease in relative time savings, some other potential services that can be provided by navigation systems are identified in Part 3. This report focuses on a particular category of users: commuters. Unfamiliar drivers can be helped by the navigation system in the task of planning and following a route. Hence, it is likely that these users perceive some significant benefits. However, commuters do not need these services and are therefore a more difficult group of users to satisfy. Some field results from the LISB Route Guidance and Information System Berlin (Al 1) indicate that a majority of users familiar with a route seldom or never perceive travel time savings, while a majority of users unfamiliar with a route always or almost always perceive travel time savings. Thus, this report focuses on benefits for commuters, although some results are applicable for other users.