The combination vehicle Practice test will examine your knowledge of driving combinations, combination vehicle air brakes, antilock brake systems, coupling and uncoupling, and inspecting combinations. In order to receive your combination vehicle endorsement, it is required that you pass the state’s official CDL written Knowledge exam.
Before you connect hose couplers 'glad hands' you should...?

Question 1 of 30

If you identify a damaged air or electrical line in your inspection, you should...?

Question 2 of 30

If you are towing a three trailer combination, the order of the cutout cocks/shutoff valves, going from the tractor backwards, should be...?

Question 3 of 30

If you have ABS only on your trailer and you lose steering control, you should...?

Question 4 of 30

You must remember that converter dollies and trailers were not required to have spring brakes if they were built before...?

Question 5 of 30

When a tractor and trailer are connected properly, there should be what space between the upper and lower fifth wheel?

Question 6 of 30

The tractor protection valve should be checked with...?

Question 7 of 30

If a trailer is too high when you try to couple, what might happen?

Question 8 of 30

Air is supplied to the emergency supply lines by...?

Question 9 of 30

When beginning to connect a tractor to a semitrailer, you should start with the tractor positioned...?

Question 10 of 30

If you have the trailer air supply knob in and the handbrake on but cannot hear air escaping from either line at the shutoff valve at the rear of the last trailer, you should first check...?

Question 11 of 30

If you are not sure whether or not your trailer has ABS brakes, you can find out by...?

Question 12 of 30

For your brakes to work properly, air supply must reach...?

Question 13 of 30

Your trailer and converter dolly will have mandatory ABS brakes if they were built after...?

Question 14 of 30

Before lowering your landing gear, you should check...?

Question 15 of 30

When checking your air brakes, it is essential that...?

Question 16 of 30

The first thing to do before testing trailer service brakes is to check for...?

Question 17 of 30

When you have connected the tractor and trailer, you can check the system for crossed air lines by applying the brakes and...?

Question 18 of 30

Having ABS brakes allows you to...?

Question 19 of 30

If the fifth wheel plate is not greased as required on a tractor semitrailer combination, it could cause...?

Question 20 of 30

The service air line is usually colored...?

Question 21 of 30

If you have ABS brakes, you can expect your braking distance to be shortened by...?

Question 22 of 30

The sliding fifth wheel on the combination vehicle must be...?

Question 23 of 30

All air tanks in an air brake system should be drained of oil and moisture at least...?

Question 24 of 30

The foot pedal on a tractor-trailer combination applies air to the service brakes...?

Question 25 of 30

In the coupling system, the locking jaw should be around...?

Question 26 of 30

When connecting a tractor to a trailer, you should have your transmission in...?

Question 27 of 30

You should always test the trailer brakes before driving with the hand valve or by pulling the air supply control. This is particularly important on...?

Question 28 of 30

You should always make sure when driving that your landing gear is...?

Question 29 of 30

You will know you have connected your hose couplers incorrectly if...?

Question 30 of 30



Studying and applying oneself is the only way to successfully learn the information you need to know to pass all testing required to obtain your CDL. We are here to help.

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