California CDL DMV Knowledge Test Class B 2

A dual air brake system is made up of two separate air brake systems. If there is an air leak in one system, it may not affect the other.

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.

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.

It is common for drivers to tailgate slow-moving vehicles that cannot keep up with the speed of surrounding traffic. If you are being tailgated, allow the other driver to pass your vehicle.

Texting while driving is particularly dangerous because it is both a mental and physical distraction to the driver. In addition to diverting a driver's mental attention away from the road, texting requires a person to remove at least one hand from the vehicle's controls.

Truck tractors with air brakes built on or after March 1, 1997 are required to be equipped with Anti-Lock Braking Systems (ABS).

Always apply the parking brake when leaving your vehicle unattended.

It is important to know the maximum air loss rate that is safe for your specific vehicle. A double combination vehicle should have a leakage rate no higher than 4 psi in a minute during an applied leakage test.

Truck tractors with air brakes built on or after March 1, 1997, and other vehicles with air brakes built on or after March 1, 1998, must be equipped with anti-lock brakes.

Without a working Anti-Lock Braking System (ABS), your vehicle will still have normal brake function. Continue to drive and brake as you normally would and have your ABS serviced as soon as possible.

If you are asked to complete an offset back/left parking maneuver, you should first pull straight forward, then back up to the left. Your vehicle must be parked completely within the boundaries of the parking space.

When checking the engine compartment during the vehicle inspection test, you will need to check the engine oil level.

While swerving can sometimes be the safest way to handle a hazard on the roadway, doing so is not without risk. Top-heavy vehicles and tractors with multiple trailers may flip over in a swerve.

An air brake system has a safety relief valve, which releases air from the tanks if the pressure gets too high. If the valve must operate, something in the system is wrong and should be addressed by a mechanic.

Compressed air usually contains a certain amount of moisture and compressor oil, which can build up in the air storage tanks and damage the brake system. The tanks should be drained to clean out these accumulations. On a tank with a manual drain valve, draining should be performed at the end of each day of driving.

If your brakes are hot after coming down a steep grade, you should not use your parking brake when parking. Let your brakes cool before applying the parking brake or risk damaging the brakes.

You will be asked to change lanes during the on-road driving test. When the examiner asks you to do this, you should make the necessary traffic checks and use the proper signals before changing lanes.

Almost any foreign object on the road poses some potential danger. For example, even something as seemingly harmless as a cardboard box could contain a hard or heavy object that could damage your vehicle.

When inspecting your windshield, you should look for cracks or other problems that could interfere with your ability to clearly see the road. The windshield wiper arms should be checked for proper spring tension. The wiper blades should be checked for damage, stiff rubber, and improper securement.

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.

Before beginning a trip, it is important to check the brake drums during your walk-around inspection. It is unsafe to drive if any brake drum has a crack more than one half of the width of the friction area.

Rust around wheel nuts may mean that they are loose. Check the tightness of the nuts if you see any rust in the area.

You should accelerate very gradually when driving under conditions that create poor traction.

You must notify your employer within two business days if your license is suspended, revoked, or canceled, or if you are otherwise disqualified from driving.

A modulating control valve allows a driver to gradually apply spring brakes. In equipped vehicles, the valve is controlled by a lever located on the dashboard.

When asked to make a lane change during the on-road driving test, you should make the proper traffic checks, use your turn signal, and smoothly change lanes when it is safe to do so.

A one-way check valve is required to be between an air compressor and the first main reservoir. This valve prevents air from escaping the system if the air compressor develops a leak.

During the on-road driving test, if your route does not include a railroad crossing, the examiner may ask you to explain and demonstrate the necessary procedures at a simulated location.

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. Cargo should be inspected every time the driver stops to take a break. The driver of a truck transporting cargo is responsible for the cargo being safely secured throughout the trip.

While driving, you should watch your vehicle's gauges for signs of trouble. Be sure to inspect your gauges before beginning a trip to ensure that they are in proper working order.

Even if they did not load or secure the cargo themselves, the driver of a vehicle is responsible for inspecting the cargo and ensuring that it is properly secured.

Be careful around pedestrians, joggers, and cyclists who are wearing headphones. They may be unable to hear your vehicle approaching and may do dangerous things because they do not know you are there.

If your vehicle has air brakes, the air compressor drive belt should be checked before each drive. Check the tightness of the belt and verify that it is in good condition.

Look at your truck's gauges when starting the engine. The oil pressure in an engine should come up to a normal level within seconds of the vehicle's engine being started.

Your vehicle's horn is a tool to warn others of your presence. Because the horn may create danger by startling other drivers, you should use it only if necessary.