Alaska CDL — General Knowledge practice
Alaska CDL — General Knowledge: Speed & Space Management practice test
Choosing a safe speed, keeping a space cushion, adjusting for weather and traffic, and understanding stopping distance.
Content reviewed against official driver handbooks · August 12, 2026
15 questions · pass with 12 correct. You get instant feedback and an explanation after every answer.
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12 sample Speed & Space Management questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.
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1. You are driving a 40-foot truck at 35 mph and count only two seconds between you and the vehicle ahead. What should you do?
Correct answer: Drop back until you have four seconds of following distance
Below 40 mph the rule is one second per 10 feet of vehicle length, so a 40-foot truck needs four seconds. A two-second count means you are too close and should ease back.
Source: Alaska Commercial Driver License Manual — Section 2.7.1, Space Ahead
2. On a slippery winter road, what speed pattern does the manual recommend?
Correct answer: Go slowly and look far enough ahead to hold a steady speed
The advice is to go slowly and watch far enough ahead that you can keep an even pace, instead of repeatedly slowing and speeding up.
Source: Alaska Commercial Driver License Manual — Section 2.13.2, Driving
3. It is below freezing and the pavement ahead looks wet. What should you watch out for?
Correct answer: Black ice
Black ice is a thin, clear layer that lets the pavement show through, so the road just looks wet. A wet-looking road in freezing temperatures is the warning sign.
Source: Alaska Commercial Driver License Manual — Section 2.6.2, Matching Speed to the Road Surface
4. Why does worn tire tread make hydroplaning more likely?
Correct answer: Shallow grooves can't carry the water away well
The grooves in the tread are what move water out from under the tire. When they are shallow they do that job poorly, so the tire rides up on the water more easily.
Source: Alaska Commercial Driver License Manual — Section 2.6.2, Matching Speed to the Road Surface
5. Of all the space around your vehicle, which does the manual call the most important?
Correct answer: The space ahead — the area you are driving into
The space in front, which you are moving into, matters most because you need room there if you have to stop suddenly.
Source: Alaska Commercial Driver License Manual — Section 2.7.1, Space Ahead
6. On a long downgrade, you are in the proper low gear and your 'safe' speed is 45 mph. Using the manual's braking technique, at about what speed do you release the brakes?
Correct answer: About 40 mph
You brake firmly enough to feel a clear slowdown, let off once you are roughly 5 mph under your safe speed, and repeat when the speed climbs back. With a 45 mph safe speed, that is about 40 mph.
Source: Alaska Commercial Driver License Manual — Section 2.16.4, Proper Braking Technique
7. Fog lies across the highway ahead. When should you reduce speed?
Correct answer: Before you enter the fog
If you must drive in fog, slow down before you reach it. The manual also warns against assuming the fog will thin once you are inside it.
Source: Alaska Commercial Driver License Manual — Section 2.12, Driving in Fog
8. On slippery roads, what does the manual say about passing slower vehicles?
Correct answer: Don't pass unless it is necessary
Under the heading on adjusting speed to conditions, the winter driving advice is to avoid passing slower vehicles unless you really have to.
Source: Alaska Commercial Driver License Manual — Section 2.13.2, Driving
9. Besides your mental and physical condition, what can greatly affect perception distance?
Correct answer: Visibility and the hazard itself
The manual notes that perception distance depends heavily on visibility and on the nature of the hazard, as well as on the driver's own condition.
Source: Alaska Commercial Driver License Manual — Section 2.6.1, Stopping Distance
10. How does the manual define traction?
Correct answer: Friction between the tires and the road
Traction is the friction between your tires and the road surface. Without it you can neither steer nor brake.
Source: Alaska Commercial Driver License Manual — Section 2.6.2, Matching Speed to the Road Surface
11. What is 'perception distance'?
Correct answer: The distance covered between the moment a hazard comes into view and the moment your brain registers it
Perception distance is the ground covered, in ideal conditions, between seeing a hazard and the brain recognizing it. Reaction distance and braking distance follow.
Source: Alaska Commercial Driver License Manual — Section 2.6.1, Stopping Distance
12. Good drivers look 12 to 15 seconds ahead. At lower speeds, about how far is that?
Correct answer: About one block
At lower speeds, 12 to 15 seconds works out to roughly a block. At highway speeds the same time span is about a quarter of a mile.
Source: Alaska Commercial Driver License Manual — Section 2.4.1, Seeing Ahead
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Every Alaska question is written from the official Alaska driver handbook and checked against its current edition. DMV Test Free is a free, independent study resource — not affiliated with any DMV or government agency. About DMV Test Free