A commercial driver is operating a 65\text{-foot} liquid bulk tanker along a rural divided… — Commercial Driver's License (CDL) General Knowledge Exam

A commercial driver is operating a $65\text{-foot}$ liquid bulk tanker along a rural divided highway at a constant cruising speed of $45\text{ mph}$ under clear, dry driving conditions. According to the standard commercial vehicle space management formula, what is the minimum safe following distance, in seconds, the driver should maintain behind the vehicle ahead?

Answer: 7.5 seconds

Answer

7.5 seconds

Under the standard commercial vehicle space management formula, drivers must allow at least

1\text{ second}

for every

10\text{ feet}

of vehicle length. For a

65\text{-foot}

tanker, the base interval is

6.5\text{ seconds}

. Because the vehicle is traveling at

45\text{ mph}

(which is at or above the

40\text{ mph}

threshold), an extra

1\text{ second}

must be added, resulting in a total minimum following distance of

7.5\text{ seconds}

Step-by-Step Solution

Calculate base following distance based on vehicle length

6.5 seconds

The standard commercial driving rule requires at least

1\text{ second}

for every

10\text{ feet}

of total vehicle length (

65 \div 10 = 6.5\text{ seconds}

Determine if additional speed adjustment is required

Add 1.0 second

For vehicle speeds of

40\text{ mph}

or greater, the rule mandates adding

1\text{ extra second}

for safety cushion due to increased stopping distance.

Sum the base time interval and the high-speed adjustment

7.5 seconds

Combining

6.5\text{ seconds} + 1.0\text{ second} = 7.5\text{ seconds}

provides the total minimum required following distance.

Key Concept

CDL Space Ahead Formula: 1 second per 10 feet of vehicle length at speeds below 40 mph, plus 1 additional second for speeds of 40 mph and above.

Estimated Time:1m 0s

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic