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Zorluk: OrtaSpace Ahead and Following Distance

A commercial driver is operating a 4040-foot straight truck at a steady speed of 30 mph30\text{ mph} along an urban corridor under ideal weather and dry road conditions. To verify following distance, the driver notes when the rear bumper of the leading vehicle passes a prominent road sign and begins counting seconds. According to commercial driving safety regulations, what is the minimum safe following distance the driver must maintain before reaching that same landmark?

  1. A
    5 seconds5\text{ seconds}
  2. 4 seconds4\text{ seconds}Cevap
  3. C
    3 seconds3\text{ seconds}
  4. D
    2 seconds2\text{ seconds}

Cevap

4 seconds4\text{ seconds}
For commercial motor vehicles, the established safety standard requires at least one second of following distance for each 10 feet10\text{ feet} of vehicle length when traveling below 40 mph40\text{ mph}. For a 4040-foot vehicle, 40÷10=4 seconds40 \div 10 = 4\text{ seconds}. Because the vehicle is moving at 30 mph30\text{ mph} (under 40 mph40\text{ mph}), no additional speed penalty second is required, resulting in a minimum safe interval of 4 seconds4\text{ seconds}.

Adım Adım Çözüm

1
Determine the base following distance required by vehicle length
40 ft10 ft/sec=4 seconds\frac{40\text{ ft}}{10\text{ ft/sec}} = 4\text{ seconds}
Commercial motor vehicle rules dictate allocating at least one second for every 10 feet10\text{ feet} of total vehicle length.
2
Evaluate operating speed to determine if the high-speed modifier applies
30 mph<40 mph30\text{ mph} < 40\text{ mph}, so no additional second is added
The one-second speed penalty only applies when traveling at or above 40 mph40\text{ mph}.
3
Calculate total minimum following distance
4 seconds4\text{ seconds}
Summing the base interval and speed adjustment yields the total required buffer.

Anahtar Kavram

CDL Space Ahead Formula: 1 second per 10 feet of vehicle length under 40 mph, plus 1 second for 40+ mph
Tahmini Süre:1m 0s
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Konular

Space Ahead and Following Distance

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