Speed Limits & Following Distance — Alaska

Alaska CDL practice test: 416 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. Updated

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 / MetricValue
TopicSpeed Limits & Following Distance
License testAlaska CDL permit (CLP) knowledge tests
Topic questions10 (2% of 416 total)
Review statusThis 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 State CDL manual (based on the AAMVA model manual) link not yet collected

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Questions (10)

1. You should maintain at least ____ of following distance per every 10 feet of your vehicle when you are traveling more slowly than 40 mph.
  1. One second ✓
  2. Two seconds
  3. Three seconds

Answer: A. One second

You should keep at least one second of following distance for every 10 feet of your vehicle when traveling below 40 mph. The handbook gives a simple space-ahead rule: below 40 mph, allow at least one second for each 10 feet of vehicle length. It illustrates this with a 40-foot vehicle needing 4 seconds and a 60-foot vehicle needing 6 seconds. When speed goes above 40 mph, the handbook says to add one more second. The bank answer matches that rule for speeds under 40 mph.
2. When traveling in heavy traffic, the safest driving speed is:
  1. The posted speed limit.
  2. The speed of surrounding traffic. ✓
  3. A speed much slower than the flow of surrounding traffic.

Answer: B. The speed of surrounding traffic.

In heavy traffic, the safest driving speed is the speed of surrounding traffic. The handbook's speed-and-traffic-flow rule says that in heavy traffic the safest speed is the speed of the other vehicles. Vehicles moving the same direction at the same speed are unlikely to run into each other. It also tells you to drive with the traffic flow if you can do so without going at an illegal or unsafe speed. That means matching surrounding traffic is the target, not simply holding the posted limit or crawling far below everyone else.
3. If you are braking on dry pavement while traveling at 55 mph, how much distance will brake lag add to your overall stopping distance?
  1. 32 feet ✓
  2. 45 feet
  3. 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.
4. What is a bobtail tractor?
  1. A tractor without a semi-trailer ✓
  2. A tractor with two semi-trailers
  3. 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.
5. When driving a 50-foot truck at 50 mph, your minimum following distance should be:
  1. Four seconds.
  2. Five seconds.
  3. Six seconds. ✓

Answer: C. Six seconds.

At 50 mph in a 50-foot truck, allow at least six seconds of following distance. The handbook's following-distance rule starts with one second for every ten feet of vehicle length, so a 50-foot truck gets a five-second base. It then says to add one second when your speed is above 40 mph. At 50 mph, that extra second brings the minimum to six seconds. The same passage shows the pattern with a 40-foot truck: four seconds normally, or five seconds over 40 mph.
6. Maintain a following distance of at least ____ for every 10 feet of your vehicle if you are traveling at a speed under 40 mph.
  1. One second ✓
  2. Two seconds
  3. Three seconds

Answer: A. One second

Official handbook: Official handbook
7. The weight of a truck:
  1. Usually has no impact on stopping distance.
  2. Is a major factor affecting stopping distance. ✓
  3. Is not as important as the type of cargo in determining stopping distance.

Answer: B. Is a major factor affecting stopping distance.

The weight of a truck is a major factor affecting stopping distance. The handbook's section on speed and stopping distance includes a discussion of how vehicle weight affects stopping distance. It says the heavier the vehicle, the more work the brakes have to do to stop it, and the more heat they absorb. That means a loaded or heavy truck takes more braking effort than a light one, so weight is a big factor in how long it takes to stop, not a minor detail you can ignore when judging your following distance and speed.
8. What is the average driver’s reaction time?
  1. 1/16 of a second
  2. 1/8 of a second
  3. 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.
9. When traveling through a work zone, you should:
  1. Slow down. ✓
  2. Speed up.
  3. Steer with one hand and keep the other hand free.

Answer: A. Slow down.

When traveling through a work zone, you should slow down. The handbook treats roadway work zones as hazardous. It says speeding traffic is the leading cause of injury and death in work zones, so you should observe posted speed limits when approaching and driving through, watch your speedometer so your speed does not creep up, and decrease speed for bad weather or when a worker is close to the roadway. Another passage says to drive slowly and carefully near work zones when people are working. That supports slowing down rather than speeding up or steering one-handed.
10. When in heavy traffic, the safest driving speed is:
  1. Slower than the speed being driven by surrounding traffic.
  2. The same speed being driven by surrounding traffic. ✓
  3. 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