Bad Weather & Night Driving — Iowa
Iowa CDL practice test: 408 free practice questions (Based on the official driver handbook). The official format is not yet verified; check the official site before your test. Bad Weather & Night Driving: 27 questions.
Rain, snow, ice, fog and night driving: visibility, traction and headlight use.
This topic page is still being reviewed against the official handbook. Until review is finished it is hidden from search engines.
| Topic / Metric | Value |
|---|---|
| Topic | Bad Weather & Night Driving |
| License test | Iowa CDL permit (CLP) knowledge tests |
| Topic questions | 27 (7% of 408 total) |
| Review status | This topic page is still being reviewed against the official handbook. Until review is finished it is hidden from search engines. |
Official handbook
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Questions (27)
1. If your vehicle is hydroplaning, you should:
- Accelerate.
- Not use the brakes. ✓
- Put the vehicle in reverse.
Answer: B. Not use the brakes.
2. If you see taillights ahead while you are driving in fog:
- The lights may not indicate where the road is as the vehicle may have pulled off the roadway. ✓
- You can assume the vehicle ahead is on the road.
- It may be an optical illusion.
Answer: A. The lights may not indicate where the road is as the vehicle may have pulled off the roadway.
The lights may not indicate where the road is, because the vehicle ahead may have pulled off the roadway. The handbook warns that taillights or headlights you see ahead in fog are not a reliable guide to the road's path. The vehicle you are following might not be on the road at all; it could be standing off to the side. That is why the handbook tells you to use roadside reflectors to help judge the curve ahead and to listen for traffic you cannot see. So you should not treat those lights as proof of where the roadway is.
3. On slippery roads, you should:
- Accelerate and slow down frequently.
- Adjust your driving to match weather conditions. ✓
- Tailgate other vehicles.
Answer: B. Adjust your driving to match weather conditions.
On slippery roads you should adjust your driving to match the weather conditions — slowing down and driving smoothly. The handbook says traction is the friction between your tires and the road, and slippery surfaces cut that traction so it takes longer to stop and is harder to turn without skidding. It tells you to drive slower on wet roads and much slower on snow or ice, to start gently, make turns gently, avoid hard braking, and allow a longer following distance. Matching your speed, turning, braking, and space to the conditions is exactly what adjusting your driving means.
4. Roads are the most slippery right after it begins to rain because:
- The water mixes with the oil and grease on the road that have not yet washed away. ✓
- Roads are naturally slippery.
- The gravel gets washed into the middle of the lane.
Answer: A. The water mixes with the oil and grease on the road that have not yet washed away.
Roads are most slippery right after rain begins because the water mixes with oil left on the road by vehicles, and that oily film has not washed away yet. The handbook's section on just after rain begins says the water combines with oil left behind by vehicles, which makes the surface very slippery. It adds that if the rain keeps falling, it washes the oil away. So the danger is highest in that first stretch of rain, before the oil is gone. That is why the choice about water mixing with oil and grease fits, and it is a traction problem you handle by slowing down on wet roads.
5. If you are driving in fog, you should not:
- Turn on the four-way flashers.
- Slow down.
- Use your high beam lights. ✓
Answer: C. Use your high beam lights.
When you are driving in fog, you should not use your high beam lights; the handbook calls for low-beam headlights and fog lights instead. The fog section of the handbook tells you to slow down before you enter fog and to run low-beam headlights and fog lights for the best visibility, even in daytime. High beams are never listed as a fog setting, so that is the action on this list you should not take. The handbook's high-beam advice belongs to clear driving: use them only when it is safe and legal, and keep them off when you are within 500 feet of an approaching vehicle.
6. Which of the following is the best advice for driving in fog?
- Try not to drive in fog. ✓
- Use your high beam headlights.
- Turn off your lights.
Answer: A. Try not to drive in fog.
The best advice for driving in fog is to try not to drive in it at all. The handbook says flatly that the best advice for driving in fog is don't. Fog can show up at any time, highway fog is very dangerous, and visibility can drop fast without warning. It is better to pull off the road into a rest area or truck stop and wait until you can see better. Only if you must drive does the handbook go on to list steps like slowing down and using low-beam headlights and fog lights.
7. When driving in fog, you should:
- Slow down. ✓
- Speed up.
- Drive on the shoulder.
Answer: A. Slow down.
Slow down when driving in fog. The handbook warns that fog can appear without warning and visibility can drop fast. It says to be ready to reduce speed and to slow down before you enter fog. If fog is bad enough, it is better to pull off the road into a rest area or truck stop than to keep driving. That supports slowing down rather than trying to drive faster or treating the shoulder as a travel lane.
8. One way to prevent hydroplaning on wet road surfaces is to:
- Ensure that your tires have good tread depth. ✓
- Under-inflate your tires.
- Drive faster than usual.
Answer: A. Ensure that your tires have good tread depth.
One way to prevent hydroplaning is to ensure that your tires have good tread depth. The handbook's inspection section says low tread depth increases the effect of hydroplaning. It also lists tread depth as an inspection item, with minimum measurements in the major grooves. So keeping adequate tread is the supported way to reduce hydroplaning, not a tire pressure change or higher speed. The driving section also says wet roads call for lower speed because traction is reduced.
9. Skids caused by acceleration can usually be resolved by:
- Accelerating.
- Removing your foot from the accelerator. ✓
- Coming to a complete stop.
Answer: B. Removing your foot from the accelerator.
To correct a skid caused by acceleration, remove your foot from the accelerator. The handbook groups acceleration skids with drive-wheel skids, where the rear wheels lose traction because of too much acceleration, often on ice or snow. It says releasing the accelerator can end this kind of skid. If the surface is very slippery, it adds that you should push the clutch in so the engine does not keep the wheels from rolling freely and regaining traction. That makes easing off the accelerator the described fix, not adding more speed or forcing a complete stop.
10. If you must drive during periods of high winds, you should:
- Loosen your grip on the steering wheel.
- Increase your speed.
- Reduce your speed. ✓
Answer: C. Reduce your speed.
When you have to drive in high winds, reduce your speed. The handbook explains that higher speed makes the impact of a crash more severe and stretches out braking distance, and that slowing down shortens the distance you need to stop. It also advises not speeding up and notes it is safer to travel at a low speed than a high one. Wind pushes a tall vehicle around, so keeping your speed down leaves you more room to correct and stop if the gusts move you. The manual does not give a separate high-wind speed rule, but its general speed guidance points to slowing down.
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Last checked: 2026-10-17 · Not yet verified
Updated: · Based on the official driver handbook