Comparing the Importance of the Factors on Drivers’ Response Time to Lead Vehicle’s Braking
During car-following, drivers respond to the braking or deceleration of a leading vehicle based on their perceived threshold for gap, relative speed, change of the gap, time-to-collision, etc. These measures are widely used to estimate drivers’ response time to the braking of a vehicle ahead. However, it is not clear if their response is driven only by absolute thresholds or also through a comparison of the current situation with any baseline situation to which they have just been exposed. This research explored drivers’ braking response to a lead vehicle’s braking using naturalistic driving data. Two hundred and ninety-six braking events were analyzed. It was found that measures adjusted from a baseline (when the lead vehicle’s brake lights were illuminated) were more important for estimating drivers’ response time than the measures on the absolute thresholds. Predictors adjusted according to the baselines are suggested for better prediction of drivers’ response time.