Abstract
A drive through gap situation was used to develop and experimentally investigate the concept of the Driver Safety Index (D.S.I.) Although little is known about the risk acceptance process in a gap situation, a risk acceptance scheme can be theorized which incorporates the gap situations, the driver factors, the vehicle factors, the driver decisions and the outcome. A mathematical equation is derived, which defines the D.S.I. for a given set of experimental conditions. The D.S.I. was used in experiments described here on visual perception, risk acceptance and driving skill.