Wisconsin CDL — General Knowledge practice
Wisconsin 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. By about how much should you reduce speed on a wet road?
Correct answer: By about one third
Cut your speed by roughly one third on wet pavement, for example from 55 down to about 35 mph.
Source: Wisconsin CDL Manual, Section 2.6.2 — Matching Speed to the Road Surface
2. Going from 20 mph up to 40 mph roughly changes your braking distance by how much?
Correct answer: It roughly quadruples
Doubling the speed roughly quadruples the braking distance and the impact force.
Source: Wisconsin CDL Manual, Section 2.6.1 — The Effect of Speed on Stopping Distance
3. At what speed can hydroplaning begin if there is enough water on the road?
Correct answer: As low as 30 mph
With a lot of water present, hydroplaning can start at speeds as low as 30 mph.
Source: Wisconsin CDL Manual, Section 2.6.2 — Matching Speed to the Road Surface
4. Total stopping distance is made up of which three parts?
Correct answer: Perception, reaction and braking distance
It is the sum of perception distance, reaction distance and braking distance.
Source: Wisconsin CDL Manual, Section 2.6.1 — Stopping Distance
5. What two things can happen if you take a curve too fast in a large vehicle?
Correct answer: You skid off the road or roll over
The tires can lose traction and slide straight off the road, or they can hold and the vehicle rolls over.
Source: Wisconsin CDL Manual, Section 2.6.3 — Speed and Curves
6. Below 40 mph, how much following distance in seconds does a 40-foot vehicle need?
Correct answer: Four seconds
At one second per 10 feet, a 40-foot vehicle needs about four seconds of following distance under 40 mph.
7. Strong winds tend to cause the most trouble staying in your lane for which vehicles?
Correct answer: Lighter vehicles
Lighter vehicles are usually affected more, and the trouble can be strongest as you emerge from a tunnel.
Source: Wisconsin CDL Manual, Section 2.7.3 — Space to the Sides
8. Regarding overhead clearance, how does an empty cargo van compare with a loaded one?
Correct answer: An empty van rides higher than a loaded one
An empty van rides higher than a loaded one, so clearing a bridge loaded does not guarantee you will clear it empty.
Source: Wisconsin CDL Manual, Section 2.7.4 — Space Overhead
9. What should be your principal method of controlling speed on a long downgrade?
Correct answer: The engine's braking effect
Rely on engine braking as your chief means of holding speed down, and save the service brakes for when they are truly needed.
Source: Wisconsin CDL Manual, Section 2.6.6 — Speed on Downgrades
10. When should you shift into a low gear for a downgrade?
Correct answer: Before you start down the grade
Move the transmission into a low gear before you start down the grade, then use proper braking technique.
Source: Wisconsin CDL Manual, Section 2.6.6 — Speed on Downgrades
11. How does the following-distance rule change once you are traveling faster than 40 mph?
Correct answer: Add one second for safety
Above 40 mph you add one extra second to the figure you get from the one-second-per-10-feet rule.
12. At speeds below 40 mph, how much following distance does the manual's rule call for?
Correct answer: One second for every 10 feet of vehicle length
Allow at least one second of space for every 10 feet of vehicle length when traveling under 40 mph.
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