While traveling at 50\text{ mph} on a dry interstate highway, the driver of a 45\text{-foo… — Commercial Driver's License (CDL) General Knowledge Exam

While traveling at $50\text{ mph}$ on a dry interstate highway, the driver of a $45\text{-foot}$ commercial motorcoach tracks a lead vehicle to evaluate space cushion management. When the rear bumper of the lead vehicle passes an overhead sign shadow, the driver counts $3.5\text{ seconds}$ before the front bumper of the motorcoach reaches the same shadow. According to standard commercial driver following distance rules, how many additional seconds of space cushion must the driver establish to maintain the minimum safe following distance?

A
$1.0\text{ second}$
$2.0\text{ seconds}$ Cevap
C
$4.5\text{ seconds}$
D
$5.5\text{ seconds}$

Cevap

2.0\text{ seconds}

The minimum safe following distance rule states that a commercial driver must allow

1\text{ second}

per

10\text{ feet}

of vehicle length at speeds under

40\text{ mph}

, plus an extra

1\text{ second}

for speeds at or above

40\text{ mph}

. A

45\text{-foot}

motorcoach traveling at

50\text{ mph}

requires

4.5 + 1.0 = 5.5\text{ seconds}

of total space cushion. Since the driver currently has a

3.5\text{-second}

interval, an increase of

5.5 - 3.5 = 2.0\text{ seconds}

is needed.

Adım Adım Çözüm

Determine the base following distance required for the vehicle length.

45\text{ ft} \div 10\text{ ft/s} = 4.5\text{ seconds}

Commercial driving standards mandate at least

1\text{ second}

of following distance for every

10\text{ feet}

of overall vehicle length.

Apply the speed adjustment for operating at or above

40\text{ mph}

4.5\text{ seconds} + 1.0\text{ second} = 5.5\text{ seconds}

For travel speeds at or above

40\text{ mph}

, an additional

1.0\text{ second}

must be added to account for increased perception, reaction, and braking distances.

Calculate the difference between the total required space cushion and the current measured interval.

5.5\text{ seconds} - 3.5\text{ seconds} = 2.0\text{ seconds}

The driver must increase headway by the deficit amount to restore the mandatory minimum following distance.

Anahtar Kavram

CDL Safe Following Distance Rule (1 second per 10 feet of vehicle length, plus 1 second for speeds at or above 40 mph).

Tahmini Süre:1m 30s

Soru

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