VALIDATING THE RESULTS OF A ROUTE CHOICE SIMULATOR

This paper describes the validation of a route choice simulator known as VLADIMIR (Variable Legend Assessment Device for Interactive Measure ment of Individual Route choice). VLADIMIR is an interactive computer- based tool designed to study drivers' route choice behaviour. It has b een extensively used to obtain data on route choice in the presence of information sources such as Variable Message Signs or In-Car Navigati on devices. The simulator uses a sequence of digitized photographs to portray a real network with junctions, links, landmarks and road signs . Subject drivers are invited to make journeys between specified origi ns and destinations under a range of travel scenarios, during which th e simulator automatically records their route choices. This paper desc ribes validation experiments carried out during the period Summer 1994 to Autumn 1995 and reports on the results obtained. Each experiment i nvolved a comparison of routes selected in real life with those driven under simulated conditions in VLADIMIR. The analysis included investi gation of the subjects' own assessment of the realism of the VLADIMIR routes they had chosen, a comparison of models based on the real life routes with models based on VLADIMIR routes, and a statistical compari son of the two sets of routes. After an extensive series of data colle ction exercises and analyses, we have concluded that a well designed s imulator is able to replicate real life route choices with a very high degree of detail and accuracy. Not only was VLADIIMIR able to precise ly replicate the route choices of drivers who were familiar with the n etwork but it also appears capable of representing the kind of errors made and route choice strategies adopted by less familiar drivers. Fur thermore, evidence is presented to suggest that it can accurately repl icate route choice responses to roadside VMS information. (C) 1998 Els evier Science Ltd. All rights reserved.