CLP Managing Space and Speed 2 — Questions and Answers
Question 1: When following another vehicle on a highway at 55 mph, what is the minimum following distance recommended for a CMV under ideal conditions?
- 4 seconds
- 5 seconds
- 6 seconds (Correct answer)
- 7 seconds
Correct answer: 6 seconds
At 55 mph, CMV drivers should maintain at least one second per 10 feet of vehicle length plus an extra second, which typically works out to 6 or more seconds.
Question 2: A loaded tanker truck is traveling at 60 mph. Compared to an empty tanker at the same speed, how does stopping distance compare?
- Loaded stops faster due to more traction
- Loaded stops in about the same distance
- Loaded may take longer to stop due to liquid surge (Correct answer)
- Loaded stops faster because brakes work harder
Correct answer: Loaded may take longer to stop due to liquid surge
Liquid surge in a loaded tanker can extend stopping distance because the shifting liquid pushes the vehicle forward even after braking.
Question 3: You are driving a 60-foot CMV at 55 mph. At minimum, how many seconds of following distance should you maintain?
- 5 seconds
- 6 seconds
- 7 seconds (Correct answer)
- 8 seconds
Correct answer: 7 seconds
The rule is one second per 10 feet of vehicle length plus one second for speeds above 40 mph: 60 ft = 6 seconds + 1 = 7 seconds.
Question 4: What is the primary reason CMVs require more stopping distance on wet roads compared to dry roads?
- Engine braking is less effective
- Tires lose traction, increasing stopping distance by up to 40% (Correct answer)
- Air brakes take longer to apply in rain
- Heavier vehicles absorb more water weight
Correct answer: Tires lose traction, increasing stopping distance by up to 40%
Wet pavement significantly reduces tire traction, which can increase stopping distance for a CMV by roughly one-third or more.
Question 5: When should a CMV driver begin reducing speed before entering a curve?
- At the start of the curve
- Well before the curve (Correct answer)
- Midway through the curve
- After the curve straightens
Correct answer: Well before the curve
Braking in a curve can cause loss of control, so CMV drivers must slow to a safe speed before entering the curve.
Question 6: A CMV is descending a long steep grade. Which technique best manages speed?
- Use the service brakes continuously at low pressure
- Shift to a higher gear and coast down
- Select a low gear before starting the descent and use engine braking (Correct answer)
- Pump the brakes every 500 feet
Correct answer: Select a low gear before starting the descent and use engine braking
Selecting a low gear before descending allows engine braking to control speed and prevents brake fade from overheating.
Question 7: What is 'brake fade' and when is it most likely to occur?
- Brakes overheat and lose effectiveness, most common on long downgrades (Correct answer)
- Brakes freeze in cold weather, most common in winter
- Brake pedal becomes spongy due to air in lines, most common after repairs
- Brakes grab suddenly, most common on wet roads
Correct answer: Brakes overheat and lose effectiveness, most common on long downgrades
Brake fade occurs when brakes overheat from excessive use, most commonly when riding the brakes on long, steep downgrades.
CLP Managing Space and Speed 2
When following another vehicle on a highway at 55 mph, what is the minimum following distance recommended for a CMV under ideal conditions?