Intersection Safety Performance Function Calibration Factors for Project Planning and Design

Project No: 124329

Target Completion Date: November 30, 2025 Safety, Operations, and Traffic Engineering

About the project:

VDOT uses the Highway Safety Manual (HSM) predictive methods to anticipate the safety performance of new intersection designs, assess the safety performance of existing intersections/corridors, or estimate the expected effectiveness of proposed improvements to existing intersections/corridors. The HSM is being updated to incorporate new models and research completed since the first edition of the manual, including safety performance functions for new configurations and traffic control types based on the results of NCHRP 17-68 Intersection Crash Prediction Methods for the HSM 2 and NCHRP 17-70 Development of Roundabout Crash Prediction Models and Methods. These SPFs need to be calibrated to Virginia conditions to ensure that they accurately reflect the driver population and environment. The purpose of this project is to conduct systematic calibration of the new intersection SPFs to be included in the 2nd HSM edition. The application of uncalibrated SPFs may produce misleading results, compromise safety outcomes, and lead to inappropriate design decisions.

Project Team

Principal Investigators

Last updated: November 18, 2023

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