Speed & Space Management

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.

1. 1. Why is the space ahead of your vehicle the most important space to manage?

   Correct answer: It is the space you most need to stop safely and can do the most about

   You are the one most likely to run into something in front of you, and a heavy vehicle needs a lot of room to stop. Keeping space ahead gives you time to see and react to trouble.

   Source: Florida CDL Handbook — Managing Space

2. 2. As a tractor-trailer turns a corner, 'off-tracking' means that the:

   Correct answer: Rear wheels follow a tighter path than the front wheels

   In a turn, the rear wheels follow a tighter path than the front wheels — off-tracking. The longer the vehicle, the more the rear wheels cut in, so you must swing wide enough to keep the trailer from striking curbs, vehicles, or objects.

   Source: Florida CDL Handbook — Turning

3. 3. How should a commercial driver handle a sharp curve?

   Correct answer: Slow to a safe speed before entering, then hold a steady speed through the curve in the right gear

   Slow to a safe speed before the curve, because braking hard within a curve can cause a skid or rollover. Choose a gear before entering so you can hold a steady, safe speed all the way through.

   Source: Florida CDL Handbook — Controlling Speed

4. 4. If you double your speed, roughly how does your braking distance change?

   Correct answer: It becomes about four times as long

   Braking distance increases with the square of speed, so doubling your speed makes the braking distance about four times as long. This is why small increases in speed matter so much.

   Source: Florida CDL Handbook — Controlling Speed

5. 5. On a long downgrade, what should provide most of your braking, and why?

   Correct answer: The engine in a low gear, with brakes used to supplement so they do not overheat

   The engine, held in a low gear, should do the main braking work, with the service brakes used only to supplement it. Riding the service brakes the whole way down overheats them and causes brake fade.

   Source: Florida CDL Handbook — Controlling Speed

6. 6. Total stopping distance for a commercial vehicle is made up of:

   Correct answer: Perception distance, reaction distance, and braking distance

   Total stopping distance is perception distance, plus reaction distance, plus braking distance. Higher speed increases all three, and braking distance grows the fastest.

   Source: Florida CDL Handbook — Controlling Speed

7. 7. To turn right safely at a tight corner in a large truck, you should:

   Correct answer: Keep to the right and swing wide only as you complete the turn, watching that no one squeezes in on your right

   Turn from as far right as is safe and swing wide only as you finish the turn, so cars cannot slip between your truck and the curb. Swinging left first invites drivers to pass on the right, where they can be crushed in the turn.

   Source: Florida CDL Handbook — Turning

8. 8. A car is tailgating your truck. What is the safest response?

   Correct answer: Increase your following distance ahead and let them pass if you can

   Open up more room ahead so you will not have to brake hard, and avoid sudden moves. If it is safe, let the tailgater pass rather than speeding up or braking to teach a lesson.

   Source: Florida CDL Handbook — Managing Space

9. 9. Why does a loaded commercial vehicle need a much larger gap to cross or enter traffic than a car does?

   Correct answer: Because it accelerates slowly and takes longer to reach traffic speed

   A heavy vehicle accelerates slowly, so it takes far longer to get up to speed and clear the way. Make sure the gap is big enough that you will not force other traffic to slow for you.

   Source: Florida CDL Handbook — Managing Space

10. 10. Before starting down a long, steep downgrade, what should a commercial driver do?

    Correct answer: Select a safe low gear before the descent begins

    Select a safe low gear before you start down, so the engine's braking effect helps control your speed. It is much harder to downshift safely once you are already rolling fast down the hill.

    Source: Florida CDL Handbook — Controlling Speed

11. 11. What happens to the following-distance rule when you drive faster than 40 mph?

    Correct answer: You add one more second to the total

    Above 40 mph you add one more second to the one-second-per-10-feet figure. So a 40-foot vehicle needs about 5 seconds when traveling over 40 mph.

    Source: Florida CDL Handbook — Managing Space

12. 12. On a wet road, how should you adjust the speed of a commercial vehicle?

    Correct answer: Reduce speed by about one-third

    Reduce your speed by about one-third on wet roads (and by about half or more on packed snow) because traction is reduced and stopping takes longer.

    Source: Florida CDL Handbook — Controlling Speed