Adjusting to Sudden Light Changes While Driving
Last reviewed: 2026 · Driviology Road Safety Education Team
Quick Answer
Slow down slightly and give your eyes a moment to adjust whenever light changes suddenly, such as entering a tunnel, facing oncoming high beams, or driving toward a low sun.
Your eyes take a moment to adjust every time lighting changes sharply. That brief adjustment period is exactly when hazards are hardest to see, so slowing down and anticipating these moments matters.
Why Sudden Light Changes Are Risky
Moving from bright sunlight into a shaded underpass, or facing an oncoming vehicle’s high beams, temporarily reduces your ability to see clearly. Night vision in particular takes longer to recover than daytime vision does.
How to Respond
- Ease off the accelerator slightly as you approach a known bright-to-dark transition.
- Look slightly away from oncoming high beams, toward the right edge of your lane, rather than staring directly at them.
- Use a sun visor or sunglasses for low-sun glare at dawn and dusk.
Managing Glare From Other Vehicles
If a vehicle behind you has its high beams on, tilt your rearview mirror to its night setting if equipped. Dip your own headlights for oncoming traffic well before you meet them, and remember that a vehicle you flashed for the same reason is likely doing you the same courtesy.