Effects of Vehicle Headlight Color on Glare and Safety

Introduction

Headlight glare is a consistent and potentially increasing concern among U.S. drivers. Most light emitting diode (LED) headlights on vehicles today have a correlated color temperature (CCT) near 6000 K (a white/bluish color), in contrast with older halogen headlights having a CCT around 3000 K and a yellowish appearance. Research suggests that while the “bluer” color of LED headlights might help drivers to see the road better and react faster in some conditions, their color also makes them more uncomfortable to look at. The AAA Foundation for Traffic Safety is working with researchers at the Light and Health Research Center at the Icahn School of Medicine at Mount Sinai to investigate this tradeoff between visibility and glare, and the relative safety impacts of headlight color.

Project Goal & Plan

The goal of this project is to determine how headlight color impacts the visual performance of drivers as well as their experience of disability glare (difficulty seeing objects) and discomfort glare. In addition to a literature review and synthesis, two laboratory experiments and a field validation study will be conducted. The first experiment will investigate the relationship between headlight color and drivers’ ability to detect objects ahead without glare. The second experiment will investigate the impact of the color of oncoming headlights, at various levels of illuminance, on drivers’ ability to detect objects in the road as well as their perceived discomfort. In the field study, findings of the laboratory experiments will be confirmed through an experiment with a real vehicle on a closed test track. The results will offer insights into safety implications of different headlight color characteristics, recommendations for transportation safety stakeholders, and actions that drivers can take to reduce glare.