Speed Limits & Following Distance — Louisiana
Louisiana CDL practice test: 410 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: 12 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 | Louisiana CDL permit (CLP) knowledge tests |
| Topic questions | 12 (3% of 410 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 (12)
1. If you are braking on dry pavement while traveling at 55 mph, how much distance will brake lag add to your overall stopping distance?
- 32 feet ✓
- 45 feet
- 20 feet
Answer: A. 32 feet
Brake lag adds 32 feet to your overall stopping distance. The handbook explains that with air brakes there is a delay while air flows through the lines before the brakes actually work. At 55 mph on dry pavement, that brake lag distance is about 32 feet. The handbook also lists brake lag as one of the four parts of total stopping distance, along with perception, reaction, and braking distance. So the added distance from brake lag is 32 feet.
2. Maintain a following distance of at least ____ for every 10 feet of your vehicle if you are traveling at a speed under 40 mph.
- One second ✓
- Two seconds
- Three seconds
Answer: A. One second
3. If a worker is present in a work zone, you should:
- Continue driving at the posted speed limit.
- Slow to a speed under the posted speed limit. ✓
- Drive in the grass.
Answer: B. Slow to a speed under the posted speed limit.
You should slow to a speed under the posted speed limit when a worker is present in a work zone. The handbook's work-zone section says speeding traffic is the leading cause of injury and death there. It tells you to observe posted limits and watch that your speed does not creep up. It also says to decrease speed for bad weather or road conditions, and to decrease it even further when a worker is close to the roadway. That extra reduction means going below the posted limit around workers.
4. Stopping distance can be affected by:
- Driving speed. ✓
- Temperature.
- Time of day.
Answer: A. Driving speed.
Driving speed affects stopping distance: as speed rises, the braking distance becomes much longer. The handbook's stopping-distance figure ties speed directly to braking distance. Going from 20 to 40 mph makes braking distance four times longer; going from 20 to 60 mph makes it nine times longer. It also says high speeds greatly increase stopping distances and that slowing down can reduce braking distance. The passage lists conditions such as traction, curves, visibility, traffic, and hills for speed adjustment, but it does not name temperature or time of day as stopping-distance factors.
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. A posted speed limit for cars:
- Is usually safe for buses.
- May be too fast for buses. ✓
- May be too slow for buses.
Answer: B. May be too fast for buses.
A posted speed limit for cars may be too fast for buses. The handbook's passenger section warns that a curve's posted speed is set with cars in mind. In good weather that number can still be too high for many buses. A bus that takes the curve too fast may roll over if traction is good, or slide off if traction is poor. That is why the car speed limit is not automatically safe for a bus.
7. How does doubling your speed from 20 mph to 40 mph affect your vehicle's braking distance?
- It stays about the same.
- It doubles.
- It quadruples. ✓
Answer: C. It quadruples.
Doubling your speed from 20 mph to 40 mph makes your braking distance four times longer, so it quadruples. The handbook's stopping-distance figure states that when you double speed from 20 to 40 mph, the impact is four times greater and the braking distance is also four times longer. It gives the same pattern for higher speeds, and it says slowing down can reduce braking distance. So the change from 20 to 40 mph is not a small increase or a doubling; the distance needed to stop grows to four times its earlier length.
8. What is the number one cause of death and injury in a work zone?
- Drivers speeding ✓
- Slow drivers
- Animals crossing the road
Answer: A. Drivers speeding
The number one cause is drivers speeding. The work zone section of the handbook names speeding as the leading source of injuries and deaths in roadway work zones. It tells you to watch the posted limit when you approach and drive through the zone, to keep checking your speedometer so your speed does not creep up on long construction stretches, and to slow further for bad weather, poor road conditions, or a worker close to the roadway. That is why speeding is the answer.
9. 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.
10. When in heavy traffic, the safest driving speed is:
- Slower than the speed being driven by surrounding traffic.
- The same speed being driven by surrounding traffic. ✓
- Faster than the speed being driven by surrounding traffic.
Answer: B. The same speed being driven by surrounding traffic.
In heavy traffic, the safest speed is the same speed the surrounding traffic is driving. The handbook says directly that when traffic is heavy you should travel at the speed of other vehicles, because vehicles moving the same direction at the same speed are not likely to run into one another. It adds that you should drive with the flow of traffic if you can do so without going at an illegal or unsafe speed. That is why matching surrounding traffic is the correct choice, not picking a speed above or below the pack.
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Last checked: 2026-10-17 · Verified from official source
Updated: · Based on the official driver handbook