Abstract
This paper describes disparity of driver behavior, which is a cause of traffic accidents, and proposes a method of quantification of the disparity with entropy. It analyzes disparity of driver behavior approaching a signalized intersection during a yellow signal period with data of positions and speeds of vehicles as well as distinction of stopping at or passing through the intersection, captured with a roadside vision-based instrument. The data show that there is a region of disparity, where vehicles of the same speeds at the same positions may stop at the intersection or may pass through it. The disparity region is identified as an intersection of two regions, each of which is defined with two dimensional Gaussian distribution for stopping vehicles versus passing vehicles. The disparity region is closely related to the conventional theoretical dilemma and option zones. The disparity in the region is quantified with entropy with respect to the speeds and the distinction. The analysis with data captured in Tokyo area suggests that disparity in the distinction is more dangerous than that in the speeds if a value of the entropy corresponds to a degree of danger.
