In Toronto, Canada, accident prediction models show that traffic-sensitive route guidance can increase crashes at low market penetrations and decrease crashes at higher market penetrations.
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Accident Risk Assessment Using Microsimulation for Dynamic Route Guidance

Summary Information

This study compared Dynamic Route Guidance Systems (DRG) with Safety-Enhanced Route Guidance Systems (SRG) using a hypothetical transportation network to measure travel time savings, throughput, and vehicle accidents. The accident characteristics data input into the hypothetical model was derived from multiple Accident Prediction Models (APM) designed from the metropolitan transportation network in Toronto, Canada. The Accident Prediction Models provided the data necessary to estimate the number of accidents based on capacity and vehicle turning movements each hour. This data was input into the hypothetical model and then network activity was measured to determine the effects of DRG and SRG on network activity.

The DRG application enabled familiar/informed drivers to receive real-time traffic information and choose routes with the least travel time. The SRG application provided familiar/informed drivers with turning decision information every five minutes and enabled them to choose routes with minimal accident risk.

Dynamic Route Guidance
  • DRG activity generated additional accidents as a result of increased link maneuvers and intersection turns. The total number of accidents in the network increased as market penetration increased and a maximum 15.5 percent increase in accidents was observed at a market penetration of 60 percent.
Safety-Enhanced Route Guidance
  • At a 20 percent market penetration rate total network accidents increased by four percent. At higher market penetration rates the number of intersection accidents dropped below baseline network levels. Overall, the SRG system reduced accidents by an average of 10 percent.
The author noted that reductions in travel time may reduce driver anxiety and offset the impact of increased accidents with increased DRG market penetration. Further examination of DRG and SRG benefits on actual transportation networks (not hypothetical) was recommended.
Goal Areas