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

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

3 / 30

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

4 / 30

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

5 / 30

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

6 / 30

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

7 / 30

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

8 / 30

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

9 / 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...?

10 / 30

Having ABS brakes allows you to...?

11 / 30

The service air line is usually colored...?

12 / 30

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

13 / 30

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

14 / 30

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

15 / 30

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

16 / 30

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

17 / 30

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

18 / 30

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

19 / 30

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

20 / 30

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

21 / 30

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

22 / 30

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

23 / 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...?

24 / 30

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

25 / 30

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

26 / 30

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

27 / 30

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

28 / 30

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

29 / 30

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

30 / 30

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

Your score is


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