Driver Behavior in Left-Turn and Other Two-Vehicle Crashes

Principal Investigator:

  • Gary Davis, Professor, Civil, Environmental and Geo-Engineering


  • Abhisek Mudgal, Post-Doctoral Associate, Civil, Environmental and Geo-Engineering

Project Summary:

During 2012, nearly 3300 crashes involving a vehicle turning left into oncoming traffic occurred in Minnesota, including more than 1100 fatal and personal injury crashes. Many agencies, including the Minnesota Department of Transportation, are interested in using a flashing yellow arrow to implement within-day changes in left-turn (LT) treatment, but this requires being able to predict how the risk of LT crashes varies at particular intersections, as traffic characteristics change during a day. This project has inter-related objectives: (1) to contribute empirical findings regarding LT gap acceptance, the trajectories followed by LT drivers, and the behavior of drivers involved in LT crashes, and (2) to develop and validate a simulation model of LT crashes that could ultimately be used to predict the safety-related effects of design or operational changes. To accomplish these, the researchers reduced video data of drivers making permitted left turns and characterized both LT gap acceptance and LT turning trajectories. These findings were then incorporated in a prototype LT crash simulation model and the model's predictions were compared to an empirical model of LT crash risk developed in a recently completed MnDOT project. The project also developed methods for quantifying uncertainty in the reconstruction of planar impact crashes and for estimating driver behavior variables from pre-crash data collected from event data recorders.

Previous related projects:

Project Details:

  • Start date: 05/2014
  • Project Status: Completed
  • Research Area: Transportation Safety and Traffic Flow

Reports or Products:

"Developing and Validating a Model of Left-Turn Crashes to Support Safer Design and Operations" (2018)

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