Washington CDL — General Knowledge practice
Washington 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
11 questions · pass with 9 correct. You get instant feedback and an explanation after every answer.
Study questions with answers
11 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. Compared with a loaded truck, why does an empty truck often need a greater stopping distance?
Correct answer: An empty truck has less traction
Empty trucks have less traction because the brakes, tires, and suspension are designed to work best when the vehicle is loaded.
Source: Washington CDL Guide — Section 2: Driving Safely (The Effect of Vehicle Weight on Stopping Distance)
2. When your speed is above 40 mph, how should you adjust your following distance?
Correct answer: Add one second for safety
At speeds over 40 mph, add one second to the following distance you would use below 40 mph.
Source: Washington CDL Guide — Section 2: Driving Safely (Space Ahead)
3. On a long, steep downgrade, what should be your principal way of controlling speed?
Correct answer: The braking effect of the engine in a low gear
Use the braking effect of the engine as the principal way to control speed on downgrades, and shift to a low gear before starting down.
Source: Washington CDL Guide — Section 2: Driving Safely (Speed on Downgrades)
4. If you take a curve too fast in a heavy vehicle, what two things can happen?
Correct answer: You skid off the road, or the vehicle rolls over
Taking a curve too fast can make the tires lose traction and slide off the road, or the vehicle can keep traction and roll over.
Source: Washington CDL Guide — Section 2: Driving Safely (Speed and Curves)
5. At what speed can hydroplaning begin when there is a lot of water on the road?
Correct answer: As low as 30 mph with a lot of water
Hydroplaning can occur at speeds as low as 30 mph when there is a lot of water on the road.
Source: Washington CDL Guide — Section 2: Driving Safely (Hydroplaning)
6. On packed snow, by about how much should you reduce your speed?
Correct answer: By about half or more
On packed snow, reduce your speed by about half, or more.
Source: Washington CDL Guide — Section 2: Driving Safely (Matching Speed to the Road Surface)
7. If your vehicle begins to hydroplane, how can you regain control?
Correct answer: Release the accelerator and push in the clutch
Release the accelerator and push in the clutch to slow down and let the wheels turn freely; do not use the brakes.
Source: Washington CDL Guide — Section 2: Driving Safely (Hydroplaning)
8. At speeds below 40 mph, how much following distance does the manual say you need for each 10 feet of vehicle length?
Correct answer: One second for each 10 feet of length
Below 40 mph, allow at least one second of following distance for each 10 feet of vehicle length.
Source: Washington CDL Guide — Section 2: Driving Safely (Space Ahead)
9. On a wet road, by about how much should you reduce your speed compared with a dry road?
Correct answer: By about one-third
On a wet road, reduce your speed by about one-third, for example from 55 to around 35 mph.
Source: Washington CDL Guide — Section 2: Driving Safely (Matching Speed to the Road Surface)
10. Why is it important to slow down before entering a curve rather than braking in it?
Correct answer: Braking in a curve makes it easy to lock the wheels and skid
Braking in a curve is dangerous because it is easier to lock the wheels and cause a skid, so slow to a safe speed before the curve.
Source: Washington CDL Guide — Section 2: Driving Safely (Speed and Curves)
11. When the road surface is icy, how should you adjust your driving?
Correct answer: Slow to a crawl and stop as soon as it is safe
If the surface is icy, reduce your speed to a crawl and stop driving as soon as you can safely do so.
Source: Washington CDL Guide — Section 2: Driving Safely (Matching Speed to the Road Surface)
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