Louisiana CDL Permit Test - Knowledge Test Class B

For safe operation, a commercial motor vehicle needs a tread depth of 4/32 of an inch in every major groove on the front tires, and a tread depth of 2/32 of an inch on other tires.

Some vehicles with air brake systems manufactured before 1975 have a front brake limiting valve with "normal" and "slippery" settings.

Factors that can affect stopping distance include the vehicle's speed, its weight, and the traction provided by the road surface.

When properly adjusted, your mirrors should each display some part of your vehicle. Being able to see your own vehicle in your mirrors will give you a point of reference when judging the positions of other objects.

In an air brake system, air tank drains are used to remove water and compressor oil from the air tanks. When operating a drain, be sure to drain the tank completely.

On flatbed trailers and trailers without sides, cargo must be tied down to prevent it from shifting or falling off in transit.

Cargo should be inspected before beginning a trip, within the first 50 miles of the trip, and every three hours or 150 miles traveled thereafter. The driver of a truck transporting cargo is responsible for the cargo being safely secured throughout the trip.