Hazardous Conditions: Rain, Ice, Fog, and Heat
Hazardous Conditions covers how weather changes traction, visibility, and braking, and the specific responses the exam expects for each.
Rain and hydroplaning
- Hydroplaning can begin around 30 mph on wet pavement, and bald or underinflated tires plane sooner.
- If the steering goes light, ease off the accelerator and hold the wheel straight. Do not brake until the tires cut through.
- Test the brakes gently after driving through standing water to dry them.
Snow and ice
- Be gentle with brakes, throttle, and steering. Do not use cruise control.
- Double the following distance and test the brakes after slush or standing water.
- Fit chains per the state chain-up rules when conditions require them.
Fog
- Slow down, use low beams because high beams reflect back, and watch the right edge line for guidance.
- Do not stop on the roadway. Get fully off the pavement and use flashers.
Worked example
You hit a puddle at 50 mph and the truck starts to float. Braking would lock the wheels and turn a straight hydroplane into a spin. Correct response: release the accelerator, keep the wheel straight, wait for the tires to reach the pavement, then brake gently and apply light pressure to dry the linings.
Traps that cost marks
- Braking during a hydroplane.
- Using high beams in fog.
- Assuming wet brakes bite at full strength on the first application.
- Using cruise control on snow or ice.