,Calibration and validation of a new time-based surrogate safety measure using fuzzy inference syste

• 作 者: Navid Nadimi Hamid Behbahani HamidReza Shahbazi
• 机 构: School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran“,”Power Electri
• 出 处: 交通运输工程学报（英文版）
• 发表日期: 2016年1期
• 关键词: Surrogate safety measure Time-to-collision Post-encroachment time Fuzzy inferenc

Surrogate safety measures (SSM) are suitable tools to detect dangerous situations. These indicators can be applied as a waing strategy in collision avoidance systems (CAS). Time-to-collision (TTC) and post-encroachment time (PET) are two important time-based SSM that identify the probability of a rear-end collision. TTC refers to the imminent danger, and PET implies the potential danger. However, sometimes the results from each indicator are inconsistent. An appropriate waing strategy for CAS can be developed using a new index that combines the properties of both TTC and PET. For this purpose, a new mixed index (MI) is proposed. In order to develop this MI, three main microscopic parameters, clearance, speed and the relative speed, are simultaneously applied to the leading vehicle. To cali-brate MI, based on a fuzzy inference system (FIS), a value would be determined by a combination of TTC and PET at each instant and then by regression analysis the model parameters would be determined. Finally, MI, TTC and PET values for real car-following scenarios on the I-80 freeway are determined and compared. The results show that MI may be more suitable in detecting the rear-end collision risk within the proper time and with less errors.