Calibrating Car-Following Models on Freeway Based on Naturalistic Driving Study

Car-following behavior is a basic micro-driving behavior. Previous researches have been devoted to modeling car-following behaviors in western countries, with few studies focused in China. Shanghai naturalistic driving study (SH-NDS) is China’s first naturalistic driving study, which provides high-precision microscopic driving behavior data. Based on SH-NDS, this paper calibrates and validates IDM and the Wiedemann model. Results show that IDM is calibrated with a high and robust performance, justifying its suitability for microscopic traffic simulation. Fundamental diagrams for IDM show that on freeways: (1) density is slightly above 40 veh/lane and flow reaches its maximum value close to 2,200 veh/h/lane; (2) jam density is about 150 veh/lane and free-flow speed is close to 100 km/h; and (3) optimal speed, related to maximum flow, approaches nearly 55 km/h. This study reveals the Chinese drivers’ driving behavior characteristics on the freeway and can contribute to the international development of car-following theory and its various applications.