Night Driving: Headlight Reach, Glare, and Fatigue
Night Driving tests visibility limits, headlight etiquette, and fatigue - the hazard that no headlight adjustment fixes.
Seeing at night
- Low beams light roughly 150 to 200 feet ahead; high beams reach about 350 to 500 feet.
- Do not overdrive your headlights. You must be able to stop inside the distance you can see.
- Dim high beams within 500 feet of an oncoming vehicle and within 200 feet when following.
Fatigue and glare
- Fatigue peaks in the early morning hours and again in mid-afternoon. Stop and rest; caffeine and cold air only postpone the problem.
- Keep the windshield and headlights clean. A dirty windshield scatters oncoming glare across your whole field of view.
- Turn down interior lighting and avoid looking directly into oncoming headlights; watch the right edge line instead.
Worked example
At 2 a.m. on a two-lane road with low beams, your total stopping distance at 55 mph is roughly 300 feet, but your low beams reach only about 200. You are overdriving the lights. Correct action: reduce speed until stopping distance fits inside 200 feet, around 40 mph, or use high beams whenever no traffic is present.
Traps that cost marks
- Using high beams in fog, rain, or snow.
- Assuming the posted limit is safe at night.
- Relying on caffeine rather than stopping to rest.
- Forgetting to dim high beams for a vehicle you are following.