Incandescent Bulb and LED Brake Lights:Novel Analysis of Reaction Times

TL;DR

This study compares reaction times to LED and incandescent brake lights, revealing that LED lights lead to faster responses, with implications for vehicle safety and brake light design.

Contribution

First to analyze reaction times split into BrakeAcc and AccPdl, showing LED brake lights improve response times over incandescent bulbs in a simulated setting.

Findings

LED brake lights result in significantly faster reaction times.

Experienced drivers respond quicker to brake light activation.

Brake light type influences both BrakeAcc and AccPdl times.

Abstract

Rear-end collision accounts for around 8% of all vehicle crashes in the UK, with the failure to notice or react to a brake light signal being a major contributory cause. Meanwhile traditional incandescent brake light bulbs on vehicles are increasingly being replaced by a profusion of designs featuring LEDs. In this paper, we investigate the efficacy of brake light design using a novel approach to recording subject reaction times in a simulation setting using physical brake light assemblies. The reaction times of 22 subjects were measured for ten pairs of LED and incandescent bulb brake lights. Three events were investigated for each subject, namely the latency of brake light activation to accelerator release (BrakeAcc), the latency of accelerator release to brake pedal depression (AccPdl), and the cumulative time from light activation to brake pedal depression (BrakePdl). To our knowledge, this is the first study in which reaction times have been split into BrakeAcc and AccPdl. Results indicate that the two brake lights containing incandescent bulbs led to significantly slower reaction times compared to the tested eight LED lights. BrakeAcc results also show that experienced subjects were quicker to respond to the activation of brake lights by releasing the accelerator pedal. Interestingly, the analysis also revealed that the type of brake light influenced the AccPdl time, although experienced subjects did not always act quicker than inexperienced subjects. Overall, the study found that different designs of brake light can significantly influence driver response times.