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Wyoming driving lesson · Defensive Driving & Conditions

Fog, rain, snow, wind and blizzards

A 4-minute lesson from the Wyoming 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 & Conditions
Checkpoint questions
6
Source pages
78, 79, 80, 92

Bad weather hides hazards and stretches stopping distances. The fixes are simple: see and be seen, slow down, add space, and avoid sudden moves. In a blizzard, the safest choice is not to drive at all.

In fog:

  • Use low beam headlights; front fog lights sometimes help
  • Use red rear fog lights only in heavy fog or similar seriously reduced visibility; turn them off after
  • Reduce speed carefully; stop at the nearest safe place if speeds may differ greatly
  • If you can't see at least 10 seconds ahead, consider pulling off at the nearest safe spot
  • Scan for taillights, headlights, pedestrians and stopped or slow vehicles; keep a big space cushion
Handbook p. 78 ↗
15 mph

Crash risk is extremely high when your speed differs from other traffic by more than this

Handbook p. 78 ↗

Know the rule

You MUST slow down on slippery roads, because stopping distances increase.

Handbook p. 79 ↗

In rain:

  • Double your following distance (cars, four seconds)
  • Use low beam headlights
  • Wait a short time after rain starts before using wipers, to avoid smearing
  • Replace wiper blades that smear or streak
  • Take care in the first half hour: dust and oil mix with water and make the road slippery
Handbook p. 79 ↗

Hydroplaning

When your tires ride on a thin film of water instead of the road. To prevent it, SLOW DOWN.

Handbook p. 79 ↗

On snow or ice:

  • Use snow tires or chains to prevent skids and shorten stopping distance
  • DON'T change speed or direction suddenly
  • Watch for ice on bridges and in shady areas
  • Triple your space on snow (cars, six seconds); quadruple it on ice (eight seconds)
  • Keep your windows clear so you can see and communicate
  • Slow gradually and smoothly before stopping or turning
  • Never lock your brakes; you can't steer unless the wheels turn
  • DON'T use cruise control
Handbook p. 79 ↗

In wind:

  • Slower speed is the best defense, especially for trucks, RVs, campers and trailers
  • Be ready to correct steering when leaving a protected area for open space
  • Expect sudden wind changes when meeting large trucks and buses
  • Be very careful on wet or slippery surfaces
Handbook p. 79 ↗

Know the rule

A blizzard combines fog-like visibility, icy roads and unexpected steering corrections. Avoid driving in one if at all possible, and listen to local radio for weather.

Handbook p. 80 ↗

If you're stranded in a blizzard:

  • Don't panic; stay with the car so you can be found more easily
  • Keep a window open a bit; freezing wet snow can seal out oxygen
  • Run the engine and heater sparingly, with a window open; keep the exhaust pipe clear of snow
  • Clap your hands and move your arms and legs vigorously from time to time
  • Use emergency flashers for work crews; turn on the dome light at night
  • Take turns keeping watch; don't all sleep at once
  • Beware of over-exertion and over-exposure
Handbook p. 80 ↗

Put it into practice

Fog thickens on the interstate until you can't see 10 seconds ahead, and traffic is slowing unevenly. Switch to low beams, slow down smoothly, and pull off at the nearest safe spot until it clears.

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.

In heavy fog, what type of headlights should you use?
  1. High beam headlights
  2. Parking lights only
  3. Low beam headlights
  4. Hazard flashers only, with headlights off

Answer: Low beam headlights

In fog, use low beam headlights; front fog lights are sometimes helpful.

Handbook p. 78 ↗
When should rear fog lights (red) be used?
  1. At all times after dark
  2. Whenever it is lightly overcast
  3. Only when parked on the shoulder
  4. In heavy fog or similar low visibility

Answer: In heavy fog or similar low visibility

Rear fog lights should only be used in heavy fog or similar hazardous weather resulting in seriously reduced visibility, and switched off once visibility improves.

Handbook p. 78 ↗
The chance of a crash in fog is extremely high whenever the difference between your speed and other traffic's speed exceeds what amount?
  1. 15 mph
  2. 5 mph
  3. 25 mph
  4. 10 mph

Answer: 15 mph

The chance of a crash is extremely high whenever the difference between your speed and the speed of other traffic is more than 15 mph.

Handbook p. 78 ↗
In rain, how should you adjust your following distance compared to dry conditions?
  1. Leave it unchanged at two seconds
  2. Double it, to about four seconds for a car
  3. Cut it in half to one second
  4. Triple it to six seconds

Answer: Double it, to about four seconds for a car

Increase your space in rain; double the time between you and the vehicle ahead, about four seconds for a car.

Handbook p. 79 ↗
What causes hydroplaning?
  1. Overinflated tires losing air suddenly
  2. Worn brake pads locking up
  3. Tires riding on a film of water
  4. A malfunctioning traction control system

Answer: Tires riding on a film of water

Hydroplaning is when a vehicle's tires ride on a thin film of water instead of the road; to prevent it, slow down.

Handbook p. 79 ↗
If you become stranded in a blizzard, what should you do about the engine and heater?
  1. Run them continuously with all windows closed
  2. Run them sparingly with a window cracked for ventilation
  3. Turn them off completely and never restart them
  4. Run them only at night

Answer: Run them sparingly with a window cracked for ventilation

Be aware of carbon monoxide; run the engine and heater sparingly, only with a window open for ventilation, and check that snow hasn't blocked the exhaust.

Handbook p. 80 ↗
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