When visibility drops, your brain struggles to judge how far away things are. In this project, ten licensed drivers each attempted to stop exactly 10 meters behind a stationary car at the end of a fog-filled lane. The test ran three times per driver — once with no rear fog lights, once with one, and once with two. Drivers misjudged distance most when rear fog lights were absent or reduced to one. Two rear fog lights produced the most accurate distance estimates.

When visibility drops in fog, drivers lose their ability to judge how far away other vehicles are. This project tests whether the number of rear fog lights on a stationary car affects how accurately drivers can estimate that 10-meter stopping distance.