Drivers' parking decisions: Advanced parking management systems

Advanced Parking Management Systems use variable, message signs to provide drivers with up-to-date information on the number of open spaces at selected parking lots throughout a city. Drivers passing a variable message sign must decide in which lot to park. Currently, it is not known what fraction will divert to each of the possible lots. This fraction is important to know, because it determines how large an affect an Advanced Parking Management System will have on traffic congestion. In this article, we report two experiments designed to test alternative models of drivers' parking decisions. Both experiments use an advanced driving simulator. This simulator makes it possible to approximate the load that drivers actually experience on the roadway so as get to a more realistic assessment of the strategies employed. Previous research had indicated that drivers use some variation of expected utility theory to select among lots. We find instead that most drivers use a lexicographic decision strategy. Such a strategy greatly reduces the cognitive load on the driver.