A Prediction Accuracy-Practicality Tradeoff Analysis of the State-of-the-art Safety Performance Assessment Methods

==Abstract==

This study proposes advanced safety assessment methods in the perspectives of prediction performance and practicality. This study thus develops three different safety assessment approaches (simulated conflicts-incorporated, estimated conflicts-incorporated, and intersection operational attributes-based safety performance function) and utilizes two existing approaches (annual average daily traffic-based and simulated conflicts-based safety performance functions. These five safety assessment approaches are compared in terms of crash prediction performance at intersections and practicality representing the required efforts in implementing a method. The results showed that the simulated conflicts-incorporated safety performance function approach was best in terms of prediction performance while the annual average daily traffic-based safety performance function approach was best in the practicality aspect. The discussion on trade-off between prediction performance and practicality then followed based on the analysis on the prediction performance and practicality aspects. This study will be a reference to safety assessment practitioners when they need to assess safety on roadways and to select an appropriate safety assessment method with limited resources.

==Keywords==

Microscopic traffic simulation model ; Traffic conflict ; Surrogate safety measures ; Safety Performance Function (SPF) ; Accuracy-practicality tradeoff

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