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.

Combination Test 02

1 / 30

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

2 / 30

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

3 / 30

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

4 / 30

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

5 / 30

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

6 / 30

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

7 / 30

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

8 / 30

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

9 / 30

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

10 / 30

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

11 / 30

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

12 / 30

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

13 / 30

The service air line is usually colored...?

14 / 30

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

15 / 30

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

16 / 30

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

17 / 30

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

18 / 30

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

19 / 30

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

20 / 30

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

21 / 30

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

22 / 30

Having ABS brakes allows you to...?

23 / 30

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

24 / 30

Before you connect hose couplers 'glad hands' you should...?

25 / 30

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

26 / 30

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

27 / 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...?

28 / 30

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

29 / 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...?

30 / 30

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

Your score is


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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