Instructions

Double

This endorsement is required if the driver will pull two or three trailers. To receive this endorsement, applicants must pass a test. The test consists of 20 multiple choice.. Read More

This endorsement is required if the driver will pull two or three trailers. To receive this endorsement, applicants must pass a test. The test consists of 20 multiple choice questions. To pass, the applicant must answer at least 16 questions correctly. Test questions come from the Commonwealth of Pennsylvania Commercial Driver’s Manual. Questions come from chapter covering: Doubles and Triples. The Double/Triple endorsement can be used with the Class A CDL.

Number of Question 20

Passing Score 16

1. A loss of air pressure in the emergency line will cause:

The service brakes to activate.

The tractor protection valve to close.

The rear trailer to detach from the combination.

The suspension springs to extend.

The tractor protection valve keeps air in the trailer's braking system should the trailer break away or develop a leak. A loss of air pressure in the emergency line will cause the tractor protection valve to open and the emergency trailer brakes to activate.

2. When approaching a railroad crossing, you should:

Increase your speed to get across the tracks as quickly as possible.

Roll your window down to listen for a train.

Rely on traffic control signals.

Never try to outdrive an approaching train.

Reduce your speed as you approach a railroad crossing. Remember that you will not necessarily be able to hear a train, and don't assume that signals will warn you of its approach. Never try to outdrive an approaching train at a railroad crossing.

3. A converter dolly that has ABS can be identified:

By a blue sticker.

By an orange sticker.

By a yellow lamp on the left side of the dolly.

By a blue lamp on the left side of the trailer.

Dollies manufactured on or after March 1, 1998 must have Anti-Lock Braking Systems (ABS). A dolly with ABS must be identifiable by a yellow lamp on its left side.

4. Why are roads especially slippery right after it begins to rain?

The water mixes with oil and grease on the road.

Roads are naturally slippery.

Gravel often gets washed to the middle of the lane.

Tires are not usually designed to drive in rain.

In rainy weather, roads are often at their most slippery when the rain first begins to fall. Fresh rainwater mixes with oil and grease on the road to form a slick film. As the rain continues, this mixture will eventually wash away.

5. Before entering a curve, you should:

Upshift.

Speed up.

Drive on the shoulder.

Downshift.

Always downshift before entering a curve. Decreasing your speed before entering the curve will allow you to maintain better control over the vehicle throughout the curve.

6. To confirm that a trailer has ABS, you can:

Look under the trailer for wheel speed sensors coming from the back of the brakes.

Look under the hood for the ABS sticker.

Look at the tires.

Remove a tire and look for the ABS sensor on the axle.

If you are unsure if a trailer is equipped with an Anti-Lock Braking System (ABS), look under the vehicle for the electronic control unit and wheel speed sensor wires coming from the back of the brakes.