Rain, fog, snow and ice

By the end of this topic you can

• You can reduce speed and increase following distance to suit the weather.
• You can use low beams, wipers and defrosters to see and be seen.
• You can recognize hydroplaning and black ice and respond calmly.
• You can recover from a skid by steering where you want to go.

What you need to know and understand

• The basic speed law in most states means you can be ticketed for driving too fast for conditions, even below the posted limit.
• California's handbook advises slowing by 5 to 10 mph on wet roads, cutting speed by half on packed snow, and going no faster than 5 mph on ice.
• California's handbook also says that if heavy weather limits your view to 100 feet or less, you should not drive faster than 30 mph.
• Roads are often most slippery in the first minutes of rain, when oil and dust mix with water.
• Bridges, overpasses and shaded spots freeze first and can hold black ice when other surfaces look dry.
• Use low beams in rain, fog and snow. Many states require headlights whenever wipers are in use: varies by state.
• Never drive through flooded roads: water depth is hard to judge and moving water can sweep a car away.

Rain and hydroplaning

In rain, slow down, leave at least double your normal following distance, and turn on your low beams. Avoid sudden braking or steering.

Hydroplaning happens when your tires ride on a film of water instead of the road. The steering may feel light. Ease off the gas, keep the wheel straight and do not brake hard until the tires grip again. Good tire tread and lower speed are your best protection.

Fog, smoke and low visibility

• Use low beams and fog lights if you have them, never high beams.
• Slow down so you can stop within the distance you can see.
• Use the right edge line as a guide, and listen for traffic you cannot see.
• Do not stop in a travel lane. If the fog becomes too thick, pull completely off the road, turn on your hazard lights and wait for it to clear.
• Avoid passing other vehicles.

Snow, ice and skids

Clear all snow and ice from windows, lights, mirrors and the roof before you set off. Accelerate, brake and steer gently, and leave a much bigger gap. Some mountain areas require chains or snow tires at times: check road signs and your state's rules.

1. If the car starts to skid, ease off the gas and do not brake hard.
2. Look and steer smoothly in the direction you want the front of the car to go.
3. With anti-lock brakes, press firmly and hold if you need to brake; without them, apply gentle pressure and release as needed.
4. Once the car straightens, continue slowly and gently.

Common mistakes

• Driving at the speed limit in heavy rain: the limit is for good conditions.
• Using high beams in fog or snow: switch to low beams.
• Braking hard on ice or when hydroplaning: ease off and steer smoothly.
• Assuming a dry-looking bridge is safe in freezing weather: slow down for black ice.
• Driving into flood water: turn around and find another route.

Test yourself: Rain, fog, snow and ice

Answer each question, then read the explanation. Questions come in a random order each time.

Go deeper

• How to Drive in Snow, Fog and Rain