Driving in fog — District of Columbia Permit Test

When it is foggy, it is best not to drive at all; if you must, reduce your normal speed, and slow down even more when you see headlights or taillights ahead.

Fog hides how close other cars are, and lights ahead mean a car you may reach sooner than you think.

Reduce your normal driving speed. Reduce speed even more when you see headlights or taillights ahead.

In fog, the vehicle with the taillights you see may be stopped or barely moving on or along the side of the road.

Taillights in fog look the same whether a car is moving or parked, so you may close on it fast.

The vehicle with the taillights may be stopped or barely moving on or along the side of the roadway.

If the fog is so thick you cannot go at least 10 mph, pull completely off the highway or stop at a rest area, service station or other parking area.

Creeping along in a traffic lane you cannot see invites a crash from behind.

If the fog is so thick you cannot go at least 10 mph, pull completely off the highway or stop at a rest area, service station or other parking area

In fog, use low beams or, if you have them, special fog lights; high beams often reflect back into your eyes and blind you.

Fog bounces strong light straight back at you, so high beams make it harder, not easier, to see.

Use low beams on headlights or, if you have them, special fog lights

In fog, be prepared for an emergency stop.

Something can appear out of fog right in front of you with almost no warning.

Be prepared for an emergency stop

Driving in fog, you see taillights ahead. What should you do?

Slow down even more. Fog hides how close other cars are, and lights ahead mean a car you may reach sooner than you think. DC Driver Manual, p.46: “Reduce your normal driving speed. Reduce speed even more when you see headlights or taillights ahead.”