Louisiana CDL DMV Knowledge Test Class B 1

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.

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.

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.

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.

It is essential that you are aware of what is happening on all sides of your vehicle at all times. Scan the road ahead and make regular checks of the mirrors on both sides of your vehicle while you are driving.

When turning on your vehicle's engine, the lights on the dash should come on and then turn off. If the ABS malfunction light stays on, the system is not working properly. In the case of a truck with a trailer, if the yellow light on the left rear of the trailer stays on once the engine has been started, the system is not working properly.

There should be at least 4/32 of an inch of tread depth in every major groove on front tires and 2/32 of an inch on other tires. Valve stems should not be cut or cracked. Tire sizes should not be mismatched.

When checking your tires as part of a pre-trip inspection, it is important to verify that the tire pressure is neither too low nor too high.

In newer vehicles with air brakes, the parking brake is controlled by a yellow, diamond-shaped knob. The driver should pull the knob outward to apply the parking brakes and push the knob inward to release them.

Cargo with a high center of gravity makes a vehicle more likely to tip over than cargo with a low center of gravity. For this reason, it is important that the weight of cargo be distributed as low as possible.

If your brakes fail while you are driving downhill, you should first look for an escape ramp to stop your vehicle. If no ramp is available, you should look for an alternative place to bring your vehicle to a stop, such as an open field or side road that flattens out or turns uphill.

Wheels or rims that have had welding repairs are not safe for use. They should be replaced before the vehicle is taken on the road.

When performing a static leakage test on a single vehicle with air brakes, the leakage rate should be no more than 2 psi in a minute. If the air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

It is important to know the maximum air loss rate that is safe for your specific vehicle. A single vehicle with air brakes should have a leakage rate no higher than 3 psi in a minute during an applied leakage test.

To avoid becoming fatigued on a long trip, you should take a break after every 100 miles or two hours of driving. Driving through the night, or during any other time when you would normally be asleep, raises the danger of fatigue.

Be sure to check your mirrors before beginning a drive. Your posture may change day to day and your mirrors may need to be adjusted.

A vehicle inspection should be completed in the same order every time. This will make it easier for you to learn all of the steps and will make it less likely that you will forget to check something.

If you see, hear, smell, or feel anything while driving that does not feel right, you should have it checked out.

When backing up, it is always a good idea for a driver to use a helper who can watch the vehicle's blind spots. The helper should stand near the back of the vehicle in a location where they are visible to the driver.

Distractions while driving can be physical (such as reaching for an object), mental (such as making conversation with a passenger), or both (such as holding a phone to send texts). Strategies to help you avoid distracted driving include pre-programming radio stations; planning out your route in advance; avoiding complex or emotionally taxing conversation while driving; adjusting your mirrors before setting out; and not eating, drinking, or smoking while behind the wheel.

As the first step of a vehicle inspection, you should review any inspection report left by the previous driver.

Transporting cargo that is loaded with a high center of gravity increases the risk that the transporting vehicle will tip over. Cargo should be loaded with a safe weight distribution.

In some emergencies, the best strategy for avoiding a hazard may be to drive onto the shoulder. Most shoulders are strong enough to support the weight of a large vehicle.

The risk of hydroplaning begins when water has collected on the surface of a road.

When driving through a work zone, follow the posted speed limits. If workers are present, you should slow to a speed that is even lower than the posted limit.

The examiner will score the number of times your vehicle touches or crosses an exercise boundary line. Each encroachment will count as an error, resulting in points against your skills test score.

Poorly balanced weight in a trailer can make handling unsafe. For example, either too little or too much weight on the front axle can make a vehicle difficult to steer. Weight should be distributed evenly from front to back and from side to side. It should be distributed as low as possible.

When exiting your vehicle during the basic vehicle control skills test, you must face the vehicle and maintain three points of contact at all times. If your testing vehicle is a bus, you must maintain contact with the handrail. Exiting the vehicle incorrectly may result in automatic failure of the basic vehicle control skills test.

The added weight of a heavy load will make a vehicle sit lower than usual. A vehicle will often be taller when carrying a light load than when carrying a heavy load. If your vehicle fits under an overpass while carrying a full load, it is not guaranteed that it will fit under the same overpass if it is empty.

If your mirrors or wiper blades become icy while you are driving, you can expect the road surface to be icy as well.

On a vehicle with one or more trailers, mirror adjustment can only be checked accurately if the trailers are straight. Mirror adjustment should be checked before the start of every trip.

If you must back up, you should exit the cab and check your path for obstacles before beginning the maneuver. Drive as slowly as you can, checking your mirrors on both sides.