Relationship Between Relative Velocity Detection and Driver Response Times in Vehicle Following Situations

Several previous studies report driver response times when responding to a lead vehicle. There have also been other studies that examined and measured the ability of drivers to detect the relative velocity of a lead vehicle. This study attempts to determine how the relative velocity detection threshold and driver response times fit together.

There may be a significant difference between the times at which a lead vehicle is visible versus when it is perceivable as an immediate hazard. This research involved two parts; the first analyzes the raw data reported in previous research. The second part involved measuring responses of subjects using a laptop simulator. The goal of both parts of this research was to compare the subtended angular velocity [SAV] with the response times of drivers to determine if there is a point (threshold) at which response times level off at a fast rate.

As theorized, driver response times remained high until the SAV of the lead vehicle increased to over 0.006 radians per second (in Part I) and to 0.0066 r/s (Part II), after which response times remained relatively fast. An in-depth analysis of driver response to a lead vehicle is discussed.