Driving in Rain & Fog
Wet pavement is involved in far more weather-related crashes than snow or ice. Rain cuts traction and visibility, and fog can hide a stopped car until it’s too late. The fix is the same for both: slow down, see and be seen, and leave more space.
- All drivers
- Work vehicles
Rain
- Turn on your headlights. Many states require headlights whenever wipers are on.
- Slow down and at least double your following distance.
- Be extra careful in the first rain after a dry spell, when oil on the road makes it slick.
- Turn off cruise control.
- Brake gently and early.
- Avoid standing water and the outside lanes where water collects.
Hydroplaning
When water builds up under your tires faster than the tread can push it away, the tires ride on the water and lose contact with the road. It can happen at moderate speeds, and worn or underinflated tires make it far more likely. See Tire Pressure & Tread.
If you hydroplane: ease off the gas, don’t brake hard or jerk the wheel, and keep steering gently in the direction you want to go until the tires grip again.
Fog
- Use low beams and fog lights. High beams reflect off the fog and make it harder to see.
- Slow down so you can stop within the distance you can see.
- Use the right edge line or road markings as a guide.
- Turn off distractions; open your window a little to listen for traffic at intersections.
- Don’t pass, and don’t change lanes unless you must.
If you can’t see
If visibility drops to almost nothing in heavy rain or dense fog, pull completely off the road as far as you safely can, ideally into a parking lot or rest area. Turn on your hazard lights. Don’t stop in a travel lane or on the shoulder where you could be rear-ended. Some highways have fog warning signs and lower speed limits during fog; follow them.
Other wet-weather hazards
- Flooded roads: never drive into water. See Flooded Roads.
- Spray from trucks can blind you for seconds; don’t linger beside them.
- Wet leaves can be as slippery as ice.
- Wipers that streak or chatter need replacing.
Standards & references
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