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Driving in fog, heavy rain and at night: what does Quebec law say?

What the Code requires when visibility drops, and the strategies the SAAQ recommends.

What the Code says

• Slow down: drivers must reduce speed when visibility is poor because of darkness, fog, rain or other precipitation, or when the road is slippery or not fully cleared (Code de la sécurité routière, Quebec’s Highway Safety Code, s. 330).
• Headlights on: at night, or when weather conditions require it, the vehicle’s headlights and lights must be on (s. 424).
• Keep your distance: follow other vehicles at a prudent and reasonable distance, taking into account weather and road conditions, among other things (s. 335).
• Driving slowly out of necessity: no one may drive so slowly that it hinders normal traffic, unless it is necessary; in that case the driver must use the hazard lights (s. 331).
• Dangerous speed: any speed or action likely to endanger people’s lives or safety, or property, is prohibited (s. 327).

Source for the points: Regulation respecting demerit points, Schedule, items 5, 8 and 9.

At night

The SAAQ manual Conduire un véhicule de promenade explains that at night contrast drops, distances are harder to judge and obstacles may be seen too late (ch. 5, “La conduite de nuit”). Its advice:

• Slow down so you can stop within the reach of your headlights, and look beyond the lit area.
• Leave more space behind the vehicle ahead.
• Keep the windshield clean inside and out, and keep your lights clean. Make sure both headlights work: with only one, another driver could mistake you for a motorcycle.
• Don’t stare at oncoming headlights: look toward the right edge of the road, and slow down if the glare is too strong.

When to switch from high beams to low beams (the 150-metre rule) is covered in our guide High beams or low beams.

In heavy rain

According to the manual, heavy rain limits what you can see and lengthens braking distance. The road is especially slippery when rain begins, as oil and other residue rise and mix with the water (ch. 5, “La pluie” and “Les surfaces glissantes”). It recommends that you:

• slow down, because maximum speed limits only apply to normal conditions;
• increase the distance behind the vehicle ahead and manoeuvre smoothly;
• turn on your low beams, even in daytime;
• avoid cruise control on a slippery surface;
• keep your wipers in good condition.

Hydroplaning

When water pools on the road, the tires can briefly lose their grip and float on the water because their grooves can no longer clear it: that is hydroplaning (aquaplanage). The driver can lose control of steering and braking. Excess speed and worn or under-inflated tires raise the risk (Conduire un véhicule de promenade, ch. 5, “Maîtriser l’aquaplanage”).

• Front-wheel drive: ease off the accelerator right away but gradually, and keep both hands on the wheel, steering where you want to go.
• Rear-wheel drive: hydroplaning is harder to feel; if in doubt, slow down and keep both hands on the wheel.

In fog

Fog hides the road and makes you harder to see; high beams create a bright wall of light in it. The manual advises (ch. 5, “La brume ou le brouillard”):

• drive slowly enough to stop within the area lit by your headlights, and increase your following distance;
• use low beams rather than high beams;
• follow the road markings, and don’t rely only on the lights of the vehicle ahead, since it could leave the road;
• signal that you are slowing by tapping the brake pedal, and avoid sudden stops;
• if the fog is very thick, stop in a safe place and turn on your hazard lights rather than leaving your high beams on.

The Guide de la route adds that you should avoid passing in mist, fog or whenever visibility is poor (ch. 4, “Le dépassement”). The “Risque de brouillard” (fog risk) sign warns of possible fog; when its lights are flashing, fog is present (ch. 3).

Moose, deer and other animals

The “Présence possible d’animaux sauvages” (wild animals possible) sign marks risk areas (Guide de la route, ch. 3). According to the SAAQ manual, animals can suddenly appear on the road, especially at night, because headlights attract them. Moose, white-tailed deer and caribou are dangerous because of their size, and a deer rarely travels alone. More than 7,000 road accidents a year are caused by white-tailed deer, moose, caribou and black bears (ch. 5, “Les animaux”).

• Be extra careful early in the morning, at dusk and in the evening, especially in May, June, October and November, and in curves, on hills and along wooded roads.
• If an animal is on the road: slow down while tapping the brakes a few times to warn drivers behind you, and use your horn to try to scare it away.

Key points for the test

• Night, fog, rain or a slippery road: slowing down is a legal duty (s. 330), not just advice.
• Headlights on at night and when the weather requires it.
• Fog: low beams, not high beams; if it is very thick, stop somewhere safe with your hazard lights on.
• Hydroplaning: ease off the accelerator gently, both hands on the wheel.
• Animals: take extra care at dawn, at dusk and at night.

See also

• Free SAAQ practice test: 15 questions
• High beams or low beams: the 150-metre rule
• Following distance and stopping distance
• Winter driving: skids and ABS brakes

Official sources

• Code de la sécurité routière (Highway Safety Code, CQLR c. C-24.2), ss. 327, 327.1, 330, 331, 335, 424, 507, 509, 510 and 512
• Regulation respecting demerit points (CQLR c. C-24.2, r. 37), Schedule, items 5, 8 and 9
• SAAQ, Guide de la route (4th ed., 2024, French), ch. 3, signs “Risque de brouillard” and “Présence possible d’animaux sauvages”; ch. 4, “Le dépassement”
• SAAQ, Conduire un véhicule de promenade (2022 ed., French), ch. 5, “La conduite de nuit”, “La pluie”, “La brume ou le brouillard”, “Les surfaces glissantes”, “Les animaux”, “Maîtriser l’aquaplanage”

General information page, current as of 2026-10-29. If in doubt, the official text prevails. Rules can change: check saaq.gouv.qc.ca and legisquebec.gouv.qc.ca.