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Zorluk: OrtaSpace Ahead and Following Distance

A driver is operating a 50-foot50\text{-foot} commercial delivery vehicle at a steady cruising speed of 55 mph55\text{ mph} along a clear, dry multi-lane divided highway. Under standard commercial driver space management guidelines, what is the minimum safe following distance the driver must maintain behind the lead vehicle?

  1. A
    4 seconds4\text{ seconds}
  2. B
    5 seconds5\text{ seconds}
  3. 6 seconds6\text{ seconds}Cevap
  4. D
    8 seconds8\text{ seconds}

Cevap

6 seconds6\text{ seconds}
According to the official CDL guidelines, a driver should allow at least 1 second1\text{ second} for every 10 feet10\text{ feet} of vehicle length at speeds under 40 mph40\text{ mph}. For a 50-foot50\text{-foot} vehicle, this base requirement is 5 seconds5\text{ seconds}. Because the vehicle is traveling at 55 mph55\text{ mph} (which is at or above 40 mph40\text{ mph}), an additional 1 second1\text{ second} must be added, resulting in a total minimum following distance of 6 seconds6\text{ seconds}.

Adım Adım Çözüm

1
Calculate base following time based on vehicle length
50 ft÷10 ft/sec=5 seconds50\text{ ft} \div 10\text{ ft/sec} = 5\text{ seconds}
The commercial vehicle guideline requires at least 1 second1\text{ second} for each 10 feet10\text{ feet} of vehicle length.
2
Evaluate operating speed to determine if speed adjustments apply
Traveling at 55 mph55\text{ mph}, which is ≥40 mph\ge 40\text{ mph}, requires +1 second+1\text{ second}
For speeds at or above 40 mph40\text{ mph}, an extra 1 second1\text{ second} must be added to provide adequate braking and maneuvering space.
3
Sum the base time and the high-speed adjustment
5 seconds+1 second=6 seconds5\text{ seconds} + 1\text{ second} = 6\text{ seconds}
The total following distance represents the minimum safe time cushion under ideal conditions.

Anahtar Kavram

CDL Following Distance Formula
Tahmini Süre:1m 0s
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