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West Virginia driving lesson · Defensive Driving and Weather

Rain, flooding, snow, wind and fog

A 4-minute lesson from the West Virginia course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.

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Read time
4 minutes
Course unit
Defensive Driving and Weather
Checkpoint questions
6
Source pages
73, 74

Bad weather cuts your traction and your visibility at the same time. Knowing when tires lose grip, how deep water floats a car, and how far you need to stop on ice keeps you out of trouble.

Know the rule

It is the law: turn on your headlights in rain and reduced visibility.

Handbook p. 73 ↗

Know the rule

Wet pavement is most dangerous at the start of a light rain, when oil, dirt and water make a slippery film that increases stopping distance and reduces grip on curves.

Handbook p. 73 ↗

Hydroplaning

Skidding on wet pavement as tires ride up on a film of water like water skis, leaving no friction to brake, accelerate, or corner.

Handbook p. 73 ↗

Hydroplaning speeds (standard passenger vehicle)

Hydroplaning speeds (standard passenger vehicle)
SpeedWhat happens
Up to 35 mphMost tires wipe the road like a windshield wiper
About 35 mphPartial hydroplaning begins
55 mphTires ride on the water; severe storm: all contact lost
Handbook p. 73 ↗

Know the rule

To reduce hydroplaning, slow down in rainstorms, slush or standing water, keep tires properly inflated, and replace tires when tread wear indicators show. Deep tread helps water escape.

Handbook p. 73 ↗
6 inches

Water deep enough to float some smaller vehicles (2 feet carries most away)

Handbook p. 73 ↗

Know the rule

Never drive across a flooded road. If you stall in floodwater, leave the vehicle immediately and seek higher ground. Trapped motorists are nearly half of U.S. flash flood deaths.

Handbook p. 73 ↗
12 times

Stopping on snow or ice can take up to this many times the dry-pavement distance

Handbook p. 73 ↗

Know the rule

Snow tires and chains don't make normal speeds safe on snow or ice. Watch for ice on bridges and overpasses, and clear and defrost all windows before driving.

Handbook p. 73 ↗

Know the rule

Brake gently on ice or packed snow. With ABS you can steer while braking. Without ABS, pump the brakes to steer, and release at the first hint of wheel slip.

Handbook p. 74 ↗

Know the rule

On snow or ice, start with low engine speed and accelerate slowly; test the brakes at low speed to judge how slippery the road is.

Handbook p. 74 ↗

Know the rule

High winds can down power lines and trees, blow debris into your path, and push you into oncoming traffic or off the road.

Handbook p. 74 ↗

In fog or dense smoke:

  • Reduce speed and be ready for an emergency stop
  • Use your low-beam headlights
  • Use your wipers to clear moisture
  • If you can't see, pull off the road, stop, and leave your lights and hazard lights on
Handbook p. 74 ↗

Put it into practice

You're driving 60 mph on the interstate in a sudden downpour and feel the steering go light. You're hydroplaning. Ease off the gas and slow down: at 55 mph in a severe storm, tires can lose all contact with the road, leaving no friction to brake or steer.

Check your understanding

Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.

At what speed does partial hydroplaning typically begin for a standard passenger vehicle?
  1. About 15 mph
  2. About 55 mph
  3. About 35 mph
  4. About 25 mph

Answer: About 35 mph

Partial hydroplaning occurs on wet roads at about 35 mph in a standard passenger vehicle.

Handbook p. 73 ↗
In a severe rainstorm, at what speed do tires lose all contact with the road (total hydroplaning)?
  1. 35 mph
  2. 55 mph
  3. 70 mph
  4. 25 mph

Answer: 55 mph

In a severe rainstorm, tires can lose all contact with the road at 55 mph, eliminating braking and steering friction.

Handbook p. 73 ↗
How much water can float some smaller vehicles, according to the handbook's flooding warning?
  1. About one foot
  2. About three feet
  3. About four inches
  4. As little as six inches

Answer: As little as six inches

As little as six inches of water can float some smaller vehicles, making flooded roads very dangerous.

Handbook p. 73 ↗
How much farther can it take to stop on snow or ice compared to dry pavement?
  1. Up to 12 times the normal distance
  2. About double the normal distance
  3. About 5 times the normal distance
  4. About the same distance

Answer: Up to 12 times the normal distance

Stopping on snow or ice can take up to 12 times the distance needed on dry pavement.

Handbook p. 73 ↗
What should you do if you must drive in fog or dense smoke?
  1. Use your high beams to see farther
  2. Speed up to get through it quickly
  3. Turn off your headlights to avoid glare
  4. Reduce speed and use low-beam headlights

Answer: Reduce speed and use low-beam headlights

In fog or smoke, reduce speed and use low beams; high beams reflect back and reduce visibility.

Handbook p. 74 ↗
Wet pavement is especially dangerous at the start of a light rain.
  1. True
  2. False

Answer: True

At the start of a light rain, oil, dirt and water mix into a slippery film on the road.

Handbook p. 73 ↗
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