New time-based surrogate safety measure to assess crash risk in car-following scenarios

Surrogate safety measures have been employed as road safety indicators for decades; numerous measures have been developed to replicate the volume and relative severity of adverse incidents in various regions. "Time-to-collision'' (TTC) is one of the most frequently used time-based surrogate safety measures. In the current study, a new application of "TTC'' has been developed for the enhancement of road safety assessment. Values for both the rate of "TTC'' variation and the level of hazard associated with "TTC'' have been amalgamated as an approximate safety indicator. A micro-simulation model is used to validate the newly developed measure with respect to the assessment of the level of safety associated with a freeway (Interstate-80). Results suggest that the developed measure more accurately considers driver car-following behavior; consequently, detection of potentially hazardous collisions is significantly improved. The proposed technique for collision prediction is shown to provide a more accurate level of risk assessment with respect to car-following scenarios; thus, it may present an opportunity for increasing the precision associated with in-vehicle collision avoidance warning systems (IVCAWS).