Impact of Dynamic and Safety-Conscious Route Guidance on Accident Risk

Under intelligent transportation systems, dynamic route guidance systems (DRG) provide routing information to motorists based on current traffic conditions on a network. Not enough attention, however, has been given to the impact of such dynamic routing decisions on network safety in terms of the predicted number of accidents. The objectives of this paper are to investigate the variation of network-wide accidents caused by traffic redistribution subject to various levels of DRG market penetration, and to examine the potential of a new safety-enhanced route guidance system. A microsimulation model was developed and integrated with a set of accident prediction models for links and intersections. Accident estimates were plotted against time to produce an accident profile that could describe the change of accident occurrence over a time period. Accident profiles, together with average travel time, were used to explain the relationships between DRG market penetration and the number of network-wide accidents. The integrated simulation model was also applied to enhance DRG by suggesting routes with the fewest estimated accidents and hence making route guidance safety conscious.