Estimation of the minimum stopping distance when braking

Abstract

In this study, we assessed drivers’ ability to estimate stopping distances for an average family car under varying speeds and road conditions. Using eight paper-and-pencil tasks, we com bined speeds (50, 70, 90, 110 km/h) with road conditions (dry or wet). Our sample consists of 1408 adults from the Republic of Srpska (50.5% women), aged 18-82 (average age 33), all of whom hold a driver’s license. Participants provided their estimated stopping distances in meters. Results revealed that most of the participants inaccurately judged stopping distances, irrespective of speed or road condition. Roughly half the estimates are within the reaction distance—the time from perceiving danger to starting to brake. 80-90% underestimated the total stopping distance. Excluding reaction distance, 50-70% of participants still underestimated the stopping distance, with errors increasing at higher speeds. This suggests participants may not understand the relationship between speed and stopping distance or recognize the two components: reaction and braking distance. Given the severe consequences of misjudgment and the fact that many drivers’ lack the experience of stop ping at high-speed driving, our findings highlight the need for enhanced driver training to improve stopping distance estimation.