Construction and Simulation of Rear-End Conflicts Recognition Model Based on Improved TTC Algorithm

In order to identify the rear-end conflicts in the freeway work zone. The traditional traffic conflict measure time to collision (TTC) can only identify the conflict risk in the situation that the speed of the following vehicle is higher than the leading vehicle. In addition, TTC is not applied to identify the potential conflict in the process of car-following due to the special road section environment of the freeway work zone. To address these limitations, time to collision in the work zone (WTTC) is proposed based on TTC. Considering the influence of the limit speed of the freeway work zone, a rear-end conflicts identification model is built based on WTTC and the deceleration rate threshold value. Then, the correlation coefficient between road risk (RR) and conflict risk (CR) is used to determine the optimal threshold of WTTC. Finally, the one-way closed work zone on Hefei Ring Expressway is selected to evaluate the identify accuracy of WTTC. The results show that compared with TTC, the accuracy of the recognition model has increased by 30% based on WTTC, which can capture more potential rear-end conflicts in the freeway work zone. Therefore, the proposed model can evaluate collision risks in the freeway work zone, and further improve the safety level of the road section.