General Knowledge Core Concepts Flashcards

What is the minimum tread depth required for front tires on a commercial motor vehicle?

Answer: 4/32 inch

Front tires on a CMV must have a minimum tread depth of 4/32 inch; all other tires require 2/32 inch.

When should you use your vehicle's low beam headlights instead of high beams?

Answer: Within 500 feet of an oncoming vehicle or 300 feet behind another vehicle

You must dim to low beams within 500 feet of an approaching vehicle and within 300 feet when following another vehicle.

A placarded hazardous materials vehicle must park how far from an open flame?

Answer: 300 feet

Vehicles carrying hazardous materials must keep at least 300 feet from an open fire unless the road requires them to pass.

Which of the following is NOT a sign of tire failure while driving?

Answer: A sudden increase in fuel economy

Improved fuel economy is not associated with tire failure; thumping, pulling, and sluggishness are all warning signs.

What does a 'gross vehicle weight rating' (GVWR) represent?

Answer: The maximum loaded weight the manufacturer specifies for a single vehicle

GVWR is the maximum loaded weight a vehicle is designed to handle, as set by the manufacturer.

What is the purpose of the 'glad hands' on a commercial vehicle?

Answer: To connect the air supply and service brake lines between a tractor and trailer

Glad hands are the coupling devices used to connect the tractor's air lines to the trailer's air lines.

Under federal hours-of-service rules, a property-carrying driver using the 60-hour/7-day limit must take how many consecutive hours off before restarting the 60-hour count?

Answer: 34 hours

A 34-hour restart (consecutive off-duty hours) resets the 60-hour/7-day or 70-hour/8-day on-duty limit.