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. Because of a large vehicle's size and slow acceleration, when you cross or enter traffic you should:

   Correct answer: Allow a much larger gap than a car would need

   A loaded truck accelerates slowly and takes a long time to clear an intersection, so you need a much larger gap than a car would to pull out or cross safely.

   Source: Georgia CDL Manual — Space to Cross or Enter Traffic

2. 2. On a long downgrade, what should be your primary means of controlling speed?

   Correct answer: The braking effect of the engine in a low gear

   The braking effect of the engine, held in a low gear, is your main speed control on a downgrade. Use the service brakes only to supplement it, because riding the brakes overheats them.

   Source: Georgia CDL Manual — Speed and Hills

3. 3. Total stopping distance for a commercial vehicle is made up of which three parts?

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

   Total stopping distance equals perception distance (seeing the hazard) plus reaction distance (moving your foot to the brake) plus braking distance (the vehicle actually stopping).

   Source: Georgia CDL Manual — Controlling Your Speed

4. 4. Why should you not simply trust the posted clearance height at a bridge or overpass?

   Correct answer: Repaving or a heavy load can make the real clearance lower than posted

   Repaving can add height to the road and a heavy load can settle the vehicle, so the real clearance may be lower than the sign shows. If you are not sure you will fit, slow down and find another route.

   Source: Georgia CDL Manual — Space Overhead

5. 5. On a wet road, by about how much should you reduce your speed?

   Correct answer: About one third

   Reduce your speed by about one third on a wet road. On packed snow, cut it by about half, and slow even more on ice.

   Source: Georgia CDL Manual — Speed and Traction

6. 6. If another driver is following you too closely (tailgating), the best response is to:

   Correct answer: Increase your following distance ahead and avoid sudden moves

   Open up more room in front of you so you have space to slow down gradually, and avoid sudden moves. Do not speed up, because a higher speed is more dangerous and the tailgater will usually just stay close.

   Source: Georgia CDL Manual — Space Behind

7. 7. Before you start down a long, steep downgrade, you should:

   Correct answer: Select a safe low gear before you start down the hill

   Select a safe low gear before you start down the hill. It is difficult and dangerous to try to downshift after speed has already built up on the grade.

   Source: Georgia CDL Manual — Speed and Hills

8. 8. If you double your speed, for example from 20 mph to 40 mph, your braking distance becomes about:

   Correct answer: About four times as long

   Braking distance grows with the square of speed, so doubling your speed roughly quadruples the distance needed to stop. This is a major reason to slow down early for hazards.

   Source: Georgia CDL Manual — Speed and Stopping Distance

9. 9. At about 55 mph on a dry road, the total stopping distance for a heavy vehicle is roughly:

   Correct answer: About the length of a football field, more than 300 feet

   Adding perception, reaction, and braking distance at 55 mph comes to more than 300 feet, about the length of a football field. That is much farther than many drivers expect.

   Source: Georgia CDL Manual — Speed and Stopping Distance

10. 10. Using the standard rule, about how much following distance should you keep for a 40-foot vehicle traveling below 40 mph?

    Correct answer: About 4 seconds

    Allow 1 second of following distance for every 10 feet of vehicle length at speeds below 40 mph. A 40-foot vehicle needs about 4 seconds.

    Source: Georgia CDL Manual — Space Ahead

11. 11. Compared with a fully loaded truck, an empty truck often:

    Correct answer: Takes a longer distance to stop because it has less traction

    An empty truck has less traction because the brakes, tires, and suspension are designed for a loaded weight. With less weight pressing the tires down, the wheels can lock up sooner, and stopping distance can actually be longer.

    Source: Georgia CDL Manual — Controlling Your Speed

12. 12. To keep space on both sides of your vehicle, you should:

    Correct answer: Avoid driving alongside others and keep an escape space open

    Avoid driving alongside other vehicles, where you could be trapped with nowhere to go, and do not travel in a pack. Keep an open space you can steer into if a hazard appears.

    Source: Georgia CDL Manual — Space to the Side