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
15 questions · pass with 12 correct. You get instant feedback and an explanation after every answer.
Study questions with answers
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.
Show all 12 questions with answers
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: Relying on 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. According to the guide, what causes the most injuries and deaths in roadway work zones?
Correct answer: Speeding traffic
Speeding traffic causes more injuries and deaths in roadway work zones than anything else, so obey the posted limits at all times.
Source: Washington CDL Guide — Section 2: Driving Safely (Roadway Work Zones)
5. 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)
6. Counting perception, reaction, and braking distance, what is the minimum distance a vehicle travels to stop from 55 mph in ideal conditions?
Correct answer: About 419 feet
Once perception, reaction, and braking distance are added up, a vehicle at 55 mph travels a minimum of about 419 feet before it stops, even in ideal conditions.
Source: Washington CDL Guide — Section 2: Driving Safely (Stopping Distance)
7. Your speed goes from 20 mph to 40 mph. What happens to your braking distance?
Correct answer: It becomes about four times as long
Doubling your speed from 20 to 40 mph makes the braking distance about four times longer.
Source: Washington CDL Guide — Section 2: Driving Safely (The Effect of Speed on Stopping Distance)
8. You are driving a 40-foot vehicle at under 40 mph. How much following distance, in seconds, should you leave?
Correct answer: 4 seconds
At one second per 10 feet, a 40-foot vehicle needs 4 seconds of following distance below 40 mph.
Source: Washington CDL Guide — Section 2: Driving Safely (Space Ahead)
9. 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)
10. 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)
11. 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)
12. 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)
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Every Washington question is written from the official Washington 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