Estimating the Likelihood of Traffic Conflicts and Crashes Using Cellular-Based Microsimulation

Recently, there have been some research interests in using cellular automata (CA) traffic models to study the occurrence of rear-end crashes by introducing unsafe driving conditions in the model. However, these CA models have unbound deceleration rates and do not permit realistic behavioral variations in the simulation. These deficiencies reduce the validity of the safety results obtained by the models. This study analyzed the likelihood of occurrence of rear-end crashes by incorporating parameters that affect driver risk-taking and alertness behaviors in the simulation model. The movements of vehicles in the model were affected by relative speeds and inter-vehicle spacings. The performance of the proposed model was evaluated by comparing speeds and spacings obtained from simulation with actual traffic data. A MAPE statistic of 9.9% was obtained upon comparing simulated speeds and spacings with actual traffic data observed in the field. The likelihood of vehicles to crash in the model was assessed by examining the time-to-collision and the rates of vehicles’ decelerations applied to avoid imminent collisions. The frequencies of simulated decelerations were fitted to a two-parameter Gamma distribution function from which the likelihood of crashes was estimated when the deceleration rate was greater than 0.6g. Simulation results indicated that there were higher chances of a vehicle being involved in a rear-end crash when traffic flow was near maximum. Future improvements the proposed model will involve increasing the authenticity of driver reactivity to traffic states using finer time steps.

• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Moses, Ren
  • Muchuruza, Victor
  • Thuo, Gikiri
• Conference:
  • Transportation Research Board 87th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2008-1-13 to 2008-1-17
• Date: 2008

Language

• English

Media Info

• Media Type: DVD
• Features: Figures; References; Tables;
• Pagination: 18p
• Monograph Title: TRB 87th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

• TRT Terms: Alertness; Cellular automata; Deceleration; Highway safety; Microsimulation; Rear end crashes; Risk taking; Traffic flow; Traffic models; Vehicle spacing
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors; I81: Accident Statistics; I83: Accidents and the Human Factor;

Filing Info

• Accession Number: 01103536
• Record Type: Publication
• Report/Paper Numbers: 08-0831
• Files: TRIS, TRB
• Created Date: Jun 24 2008 11:42AM