Under standard CDL safety guidelines, operating a 40-foot commercial vehicle at a speed of… — Commercial Driver's License (CDL) General Knowledge Exam

Under standard CDL safety guidelines, operating a $40$ -foot commercial vehicle at a speed of $45\text{ mph}$ on a dry, level highway requires a minimum following distance of at least $5\text{ seconds}$ .

Answer: Answer

Answer

True, because the vehicle length calculation yields

4\text{ seconds}

(

40\text{ ft} \div 10

) plus

1\text{ additional second}

for traveling at or above

40\text{ mph}

, totaling

5\text{ seconds}

The statement is true because the standard commercial motor vehicle formula mandates

1\text{ second}

for each

10\text{ feet}

of length plus

1\text{ additional second}

for traveling at

40\text{ mph}

or faster (

4\text{ seconds} + 1\text{ second} = 5\text{ seconds}

Step-by-Step Solution

Calculate the base following distance based on vehicle length

40\text{ ft} \div 10\text{ ft/second} = 4\text{ seconds}

CDL guidelines allocate one second of space for every ten feet of vehicle length.

Apply the speed-dependent modifier for speeds at or above 40 mph

Add

1\text{ second}

(

4\text{ seconds} + 1\text{ second} = 5\text{ seconds}

)

Speeds of 40 mph or greater require one additional second of following distance to account for increased stopping distance.

Compare calculated required following distance with the statement

Calculated value of

5\text{ seconds}

matches the statement requirement

The statement correctly reflects the established safety threshold.

Key Concept

Commercial Vehicle Following Distance Formula

Estimated Time:1m 0s

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