Operating oil pressure should be between 35 and 75 psi. Do not operate a vehicle if it has oil pressure that is low, dropping, or fluctuating.

Combination vehicles are usually heavier and longer than single combination vehicles. Operating a combination vehicle requires a higher level of driving skill than operating a single commercial vehicle.

If you must stop on the side of the road, you must place the appropriate emergency warning devices within 10 minutes of stopping.

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.

If you must drive onto the shoulder to avoid a hazard, stay on it until you come to a stop; then signal, check your mirrors, and merge back into traffic. Avoid braking on the shoulder at speeds higher than about 20 mph. To help maintain control, always keep one set of wheels on the pavement, if possible.

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.

Wheels or rims that have had welding repairs are not safe to be used.

An Anti-Lock Braking System (ABS) helps prevent wheels from locking up during a hard application of brakes.

Packaging can be an indicator of whether or not materials are hazardous. Cylinders and drums are often used to hold and transport hazardous materials.

Because air pressure increases with temperature, you should pay special attention to the tire mounting and pressure when traveling in hot weather.

If your brakes fail on a downgrade, you will need to quickly find something outside that can stop your vehicle. An escape ramp is the best option. If no escape ramp is available, use the least hazardous available option, such as driving into an open field or side road that flattens out or turns uphill.

During the vehicle inspection test, you will be required to do a complete inspection of your vehicle. During this inspection, you must explain to the examiner what you are inspecting and why you are inspecting those items.

Because liquid tanks can be vulnerable to surge, it is important to begin braking well in advance of a stop. Increase your following distance to reduce the need to stop suddenly.

Rust around wheel nuts can indicate that the nuts are loose. If you find rust near the wheel nuts, check their tightness before beginning to drive.

When inspecting your vehicle's suspension, verify that leaf springs do not have missing or broken leaves. If at least one-fourth of the leaves in a leaf spring are missing, the vehicle will be put out-of-service until the defect is fixed.

If you are transporting hazardous waste, you must carry with you a Uniform Hazardous Waste Manifest. The manifest must be signed by hand.

Except when parking briefly to perform necessary functions for vehicle operation (such as refueling), never park a vehicle carrying Division 1.1, 1.2, or 1.3 explosives within 300 feet of a bridge, tunnel, or building. Never park such a vehicle within five feet of the traveled portion of the road.

A tractor protection valve keeps air in a tractor or truck air brake system should the trailer break away or develop a bad leak. The valve will close automatically if the pressure drops to an unsafe level.

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.

If you remain in neutral for too long while switching gears, you may have difficulty putting the vehicle into the next gear. If this happens, do not try to force the gear shift. Instead, return to neutral, release the clutch, increase the engine speed to match the road speed, and try again.