How to Drive in Fog in Ontario

Fog reduces visibility more severely and suddenly than most other weather conditions. You can go from clear to near-zero visibility in seconds when driving through dense fog patches. Unlike rain, fog also creates a false sense of stillness, and drivers tend to underestimate how fast they are going. Multi-vehicle collisions in fog often happen because one driver stops and the next one does not see them until it is too late.

This is the most important rule for fog driving. High beams reflect off the water droplets in fog and create a bright wall of white light directly in front of you, dramatically reducing your forward visibility. Low beams project light downward and forward, cutting under the fog layer and illuminating the road ahead much more effectively. Some vehicles have dedicated fog lights that work even better than standard low beams.

Reduce your speed well below the posted limit in fog. Your visibility determines your safe speed: you should be able to stop within the distance you can clearly see. Increase your following distance to 4 or more seconds. In severe fog, the only warning you may have that a vehicle has stopped is the brief appearance of brake lights before you reach them.

When visibility is severely limited, lower your radio volume and open your window slightly so you can hear approaching traffic, especially at intersections. In very dense fog, roll through intersections slowly even if you have a green light, because cross-traffic may not stop in time if they cannot see the signal.

If visibility drops to less than 30 metres, consider pulling over entirely. Do not stop on the shoulder of a highway if possible: park in a parking lot, rest area, or side street. If you must stop on the shoulder, turn your headlights off (so following drivers do not mistake you for a moving car) and turn on your hazard lights. Wait for conditions to improve before continuing.