Developing a New Surrogate Safety Indicator Based on Motion Equations

  • Hamid Behbahani Professor School of Civil Engineering, Iran University of Science and Technology
  • Navid Nadimi Ph.D. candidate, Department of Civil Engineering Iran University of Science and Technology
  • Hooman Alenoori Research assistant, Parseh Transportation Institute
  • Mina Sayadi Research assistant- Babol noshirvani university of technology
Keywords: time-to-collision, Collision avoidance systems, car-following, motion equation,


Collision avoidance system (CAS), with the help of surrogate safety measures is a beneficial tool for reducing driver errors and preventing rear-end collisions. One of the most well-known surrogate safety measures to detect rear-end conflicts is Time-to-collision (TTC). TTC refers to the time remaining before the rear-end accident if the course and the speed of vehicles are maintained constant. Different surrogate measures have been derived from TTC; however, the most important are Time Exposed Time-to-collision (TET) and Time Integrated Time-to-collision (TIT). In this paper a new surrogate safety measure based on TTC notion has been developed. This new indicator merges TET and TIT into one measure and gives a score between 0 and 100%, as the probability of collision. Applying this indicator in CAS as a safety measure will be more useful than TET&TIT, to reduce driver errors and rear-end collisions.


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How to Cite
Behbahani H, Nadimi N, Alenoori H, Sayadi M. Developing a New Surrogate Safety Indicator Based on Motion Equations. Promet - Traffic&Transportation. 2014;26(5):371-8. DOI: 10.7307/ptt.v26i5.1388