Headlight glare on highways can make it hard to see clearly. Tests showed that glare from headlights can affect how well drivers can see the road. The brightness of the glare matters - if it's too bright, visibility decreases. Current headlights can produce glare that is much brighter than what is safe for good visibility. To see well on the road, it's important to reduce glare from other cars. This research suggests that safer headlighting is needed to improve highway visibility.