Speed Limits & Following Distance — 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. Speed Limits & Following Distance: 10 questions.
Posted speed limits, school and construction zones, stopping and following distance.
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 | Speed Limits & Following Distance |
| License test | Iowa CDL permit (CLP) knowledge tests |
| Topic questions | 10 (2% 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
Not yet verified
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Questions (10)
1. An Individual Vehicle Distance Record (IVDR) does not need to include which of the following?
- The dates of a trip
- The total distance traveled
- The number of vehicles passed ✓
Answer: C. The number of vehicles passed
An Individual Vehicle Distance Record does not need to include the number of vehicles passed. The handbook describes the IVDR as a trip record that shows the distance traveled and the fuel purchased for a vehicle running interstate under apportioned registration and IFTA credentials. It also says that although the layout of the form can differ, the information required for proper record keeping stays the same, and the licensee must keep records that back up the quarterly tax return. Counting the vehicles you pass has nothing to do with miles driven or fuel burned, so it falls outside what the record is meant to capture.
2. The leading factor resulting in death and injury in work zones is:
- Speeding. ✓
- Stopping.
- Under-inflated tires.
Answer: A. Speeding.
Speeding is the leading factor in deaths and injuries in work zones. The work zone section of the handbook states plainly that speeding traffic is the number one cause of injury and death in roadway work zones. Because of that, it tells drivers to obey posted limits when approaching and moving through a work zone, to keep an eye on the speedometer so their speed does not creep up during long construction stretches, and to slow further in bad weather or when a worker is near the road.
3. If you are being tailgated while driving a large vehicle, do all of the following, except:
- Reduce your speed gradually.
- Increase your following distance.
- Increase your speed. ✓
Answer: C. Increase your speed.
Increase your speed is the one thing you should not do when a vehicle is tailgating you. The handbook's advice for a tailgater starts with avoiding quick changes: signal early and bring your speed down gradually rather than suddenly. It also says to open up the room in front of you, because that extra space means you won't have to make abrupt speed or direction changes and it gives the tailgater an easier chance to pass. On speeding up, the handbook is direct: don't. Being followed closely is safer at a low speed than at a high speed. So the item that does not belong on the list is increasing your speed.
4. A ramp's posted speed limit:
- Is suitable for all vehicles.
- Is suitable for some vehicles, but may be too fast for a large CMV. ✓
- Is just a suggestion and may be exceeded.
Answer: B. Is suitable for some vehicles, but may be too fast for a large CMV.
A ramp's posted speed limit is suitable for some vehicles, but it may be too fast for a large CMV. The handbook says off ramps and on ramps often have posted speed limit signs, and it warns that those speeds may be safe for automobiles but may not be safe for larger or heavily loaded vehicles. That is why the sign is not a guarantee for your truck. A downhill exit that also turns is especially risky because the downgrade makes it hard to slow down, and braking while turning is dangerous. The safe approach is to be going slowly enough before you reach the curved part of the ramp.
5. If a speed limit is posted, the posted speed:
- Should never be exceeded. ✓
- May be exceeded if passing another vehicle.
- May be exceeded if driving in a rural area.
Answer: A. Should never be exceeded.
When a speed limit is posted, you should never exceed it. The handbook states plainly that if a speed limit is posted, or a sign shows a "Maximum Safe Speed," you must never go faster than the speed shown. The same section tells you to watch your speedometer so your speed does not creep up through long work zones, and to slow further for bad weather or road conditions. So the posted number is a ceiling you stay under, not a target to beat when it suits you.
6. On a slippery surface, stopping distance:
- Is longer than on a regular driving surface. ✓
- Is not as long as on a regular driving surface.
- Is about the same as on a regular driving surface.
Answer: A. Is longer than on a regular driving surface.
On a slippery surface, stopping distance is longer than on a regular driving surface. The handbook says traction is the friction between tires and the road, and slippery conditions reduce it. It states directly that it will take longer to stop when the road is slippery, and wet roads can double stopping distance. That is why you must slow down to stop within the same distance you would need on a dry road. The correct choice simply matches that rule: a slippery surface makes the stop take more distance, not less.
7. Scan the road ____ ahead of your vehicle.
- Two to three seconds
- Five to six seconds
- 12 to 15 seconds ✓
Answer: C. 12 to 15 seconds
Scan the road 12 to 15 seconds ahead of your vehicle. The handbook says most good drivers look far enough ahead to cover the distance they will travel in 12 to 15 seconds. At lower speeds that is roughly one block, and at highway speeds it is about a quarter mile. Looking that far gives you room to stop or change lanes without sudden moves. It also says you should not ignore nearby traffic; good drivers move their attention between near and far. A two-to-three-second or five-to-six-second scan is shorter than the handbook's guideline.
8. What is a bobtail tractor?
- A tractor without a semi-trailer ✓
- A tractor with two semi-trailers
- A tractor that travels faster than the speed limit
Answer: A. A tractor without a semi-trailer
A bobtail tractor is a tractor without a semi-trailer. The handbook uses the term bobtail for a tractor that is running without a semi-trailer attached. It also warns that these tractors can be hard to stop smoothly and may take longer to stop than a fully loaded tractor-semitrailer. That description matches a tractor with no trailer, not a tractor pulling one or two trailers.
9. What is the average driver’s reaction time?
- 1/16 of a second
- 1/8 of a second
- 3/4 of a second ✓
Answer: C. 3/4 of a second
The average driver's reaction time is 3/4 of a second, which is the low end of the range the handbook gives. The handbook's discussion of stopping distance breaks the total into perception distance, reaction distance and braking distance. For reaction distance, it states that the average driver takes 3/4 second to 1 second to react before physically hitting the brakes, and notes that at 55 mph this accounts for 61 feet of travel. Since 3/4 of a second is the figure the handbook lists first for an average driver, it is the answer here. Reaction time is separate from perception time, which the handbook puts at 1 3/4 seconds for an alert driver.
10. One way to prevent a surge is to:
- Brake in well advance, eliminating sudden stops. ✓
- Accelerate quickly.
- Drive below the speed limit.
Answer: A. Brake in well advance, eliminating sudden stops.
Brake well in advance of a stop so you avoid sudden stops, which helps prevent liquid surge. For tank vehicles, the handbook explains that the liquid can surge because of the high center of gravity. It says you must start, slow down, and stop smoothly. To control surge, it advises keeping steady pressure on the brakes, not releasing too soon, braking far in advance of a stop, and increasing following distance. Braking early and avoiding sudden stops fits that guidance because it keeps the stop smooth and reduces the back-and-forth movement of the liquid.
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Last checked: 2026-10-17 · Not yet verified
Updated: · Based on the official driver handbook