Oklahoma CDL DMV Endorsement Double 1

If your trailer begins to drift while you are backing, you should correct the drift immediately by turning the top of the steering wheel in the direction of the drift.

The trailer hand valve, also called the trolley valve or Johnson bar, is used to work the trailer brakes. It should be used only to test the brakes. Using it while a vehicle is in motion could cause a skid.

Landing gear, or trailer supports, should always be completely raised before a vehicle is driven. When uncoupling, landing gear should be lowered to make firm contact with the ground. If a trailer is loaded when it is being uncoupled, you should lower the landing gear and turn the crank a few additional times to remove some weight from the trailer.

When coupling air brake hoses, you should make sure the proper pairs of gland hands are connected. They are sometimes color-coded to help drivers avoid mistakes. Typically, blue is used for service lines and red is used for emergency lines.

When positioning trailers in a combination, the most heavily-loaded trailer should be the closest to the tractor. The lightest trailer should be positioned in the rear.

Roads are particularly slippery when it first begins to rain. The water mixes with oil drippings on the road that have not yet washed away, creating a slippery and dangerous mixture.

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.

If you have an Anti-Lock Braking System (ABS) equipped on only the tractor, only the trailer, or only one axle, you will still have more control over the vehicle when braking than you would without ABS. You should brake normally.

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.

A large vehicle requires more space when entering or crossing traffic than a smaller vehicle. This is not only because the vehicle itself is larger, but also because it needs a longer distance to accelerate.

In an air brake system, air tanks have drains to remove accumulations of water and compressor oil. Allowing water and oil to accumulate in the system could cause damage to the brakes.

Splitting driving responsibilities with a second driver lowers the chance that either of you will drive while fatigued. You can also reduce the risk of fatigue by avoiding heavy foods and keeping the interior of the cab cool.

A vehicle's total stopping distance is made up of perception distance, reaction distance, brake lag distance, and braking distance. With all of these factors included, an air brake-equipped vehicle traveling at a speed of 55 mph under ideal driving conditions will need approximately 450 feet to come to a complete stop.

All commercial motor vehicles are required to be equipped with the proper emergency equipment. This may include spare electrical fuses; three red reflective triangles, six fuses, or three liquid burning flares; and at least one properly charged and rated fire extinguisher.

In general, you should always use the parking brake when parking your vehicle. However, you should not apply the parking brake if your brakes are very hot or if your brakes are wet and temperatures are below freezing.

If your vehicle begins to hydroplane, do not apply the brakes. Instead, slow down by releasing the accelerator and pushing in the clutch. This will help you to regain traction.

Vehicles with trailers are vulnerable to rollover due to the "crack-the-whip" effect, which is caused by rearward amplification. Rearward amplification varies from vehicle to vehicle, so it is important that drivers are aware of the rearward amplification of their specific vehicles.

Front wheel braking is effective under all road conditions. It is unlikely that you will experience a front wheel skid, even on ice.

It is important to observe other drivers' actions and identify clues that a person could be driving impaired. Drivers who have had too much to drink, are sleepy, are on drugs, or are ill can present hazards to other drivers. One sign that a driver may be impaired is that they have their windows rolled down in cold weather.

Your truck may block the views of drivers behind you, making them unaware of any upcoming hazards that require you to stop. For this reason, it is a good idea to flash your brakes and warn other drivers before slowing or stopping.