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

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.