California Driver Handbook - Special Driving Situations
Slow down when there is a lot of water on the road. In a heavy rain at speeds of 50 mph or more, your tires can lose all contact with the road and then your vehicle will be riding on water or “hydroplaning.” A slight change of direction, applying the brakes, or a gust of wind could throw your vehicle into a skid.
If your vehicle starts to hydroplane, slow down gradually—do not apply the brakes.
Slow down at the first sign of rain, especially after a dry spell. This is when many roads are the most slippery, because oil and dust have not washed away. A slippery road will not give your tires the grip they need. Drive more slowly than you would on a dry road. Adjust your speed as follows:
- Wet road–go 5 to 10 mph slower.
- Packed snow–reduce your speed by half.
- Ice–slow to a crawl.
Some road surfaces are more slippery than others when wet and usually have warning signs posted. Here are some clues to help you spot slippery roads:
- On cold, wet days, shade from trees or buildings can hide spots of ice. These areas freeze first and dry out last.
- Bridges and overpasses tend to freeze before the rest of the road does. They can hide spots of ice.
- If it starts to rain on a hot day, the pavement can be very slippery for the first several minutes. Heat causes oil in the asphalt to come to the surface. The oil makes the road slippery until the rain washes the oil off the surface of the road.
High winds can be a hazard while driving, especially to larger vehicles, such as trucks, campers, and vehicles with trailers. Some precautions for driving in high winds include:
- Reduce your speed. Slowing down gives you better control over the vehicle and will give you more time to react in the event your vehicle gets hit by a strong gust of wind.
- Maintain a firm hand position on the steering wheel. Strong wind gusts are unpredictable, and if you are not holding the wheel properly, gusts can be strong enough to cause the steering wheel to be jerked out of your hands.
- Be alert. Look well ahead and watch for any debris on the road. High winds can cause debris to litter the highway or can even throw debris directly into your path. By looking ahead you give yourself more time to react to road hazards.
- Not using cruise control. You can maintain maximum control of the accelerator (gas) pedal when unpredictable gusts of wind occur.
- Be proactive. Wait for the storm to blow over. It may be safer to pull over and take a break.