Alabama CDL DMV Endorsement Double 2

A trailer tends to swing around, potentially resulting in a trailer jackknife, if its wheels lock up.

Before a trip, you should ensure that air reaches all air brakes on all trailers by opening up the rear emergency line and service line shut-off valves and listening for escaping air. Close both shut-off valves before beginning to drive.

Before driving a vehicle with a dual air system, allow time for the air compressor to build up a minimum pressure of 100 psi in both the primary and secondary systems.

To lower the risk of a rollover, load your cargo as closely to the ground as possible. To further reduce this risk, take curves and corners slowly.

Swerving out of the way of a hazard is sometimes safer than trying to stop before reaching the hazard. You can usually turn away from something more quickly than you can come to a complete stop.

To prevent the build up of oil and water in a vehicle's air tanks, manually operated air tank drains should be used at the end of each day of driving.

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.

If a converter dolly has spring brakes, you can release the brakes by using the dolly parking brake control. Releasing the dolly's brakes is the first step you should take when properly positioning the dolly in front of the rear trailer.

Never unlock the pintle hook with the dolly still under the rear trailer. This could cause the dolly tow bar to fly up, possibly causing serious injury.

In heavy traffic, it is safest to travel at the same speed as other vehicles. If two vehicles continue to drive in the same direction at the same speed, they cannot hit each other.

During a pre-trip inspection, you should check for emergency equipment, including spare electrical fuses; three red reflective triangles, six fuses, or three liquid burning flares; and at least one properly charged and rated fire extinguisher.

If you must stop on the side of the road, make sure to use your four-way emergency flashers. This is particularly important at night.

If a converter dolly has air brakes, you can release the brakes by opening the dolly air tank petcock. Releasing the dolly's brakes is the first step you should take when properly positioning the dolly in front of the rear trailer.

If a converter dolly has spring brakes, you can release the brakes by using the dolly parking brake control. Releasing the dolly's brakes is the first step you should take when positioning the dolly in front of the rear trailer.

When inspecting the convertor dolly, ensure that all components are present and in proper working condition. Be sure to check the upper and lower fifth wheel, the air lines, and the electric lines. The air lines should be securely attached to the proper glad hands and should not contain any leaks. They should be attached with enough slack to allow easy turning.

Trailers and converter dollies manufactured on or after March 1, 1998 are required to have Anti-Lock Braking Systems (ABS).

The service air line carries air and is controlled by either the foot brake or trailer hand brake. The service air line is attached to relay valves, which allow the trailer brakes to be applied quickly.

When making a turn, be sure to steer gently and smoothly. Making a quick turn while pulling trailers is dangerous and can increase the risk of the last trailer rolling over.

It is best to avoid driving through large puddles or moving water. If there is no way to avoid driving through water, you should slow down, shift into a low gear, and gently apply the brakes. Pressing linings against the brake drums or discs will keep water, mud, silt, and sand from getting inside the brake mechanisms.

To avoid being blinded by the lights of oncoming vehicles, you can glance to the right side of the road until the vehicle has passed.