cdl practice test

Combination Vehicles CDL Test


Question #1 of 49

Charge the trailer air brake system and check that the trailer rolls freely. Then stop and pull out the trailer air supply control valve. Pull gently on the trailer with the tractor to check that the trailer emergency brakes are on.


This is not a test.

This is how can you test the tractor protection valve.

This is how can you test the trailer emergency brakes.

This is how can you test that air flows to all trailers.

This is how can you test the trailer service brakes.



About this Combination Vehicles CDL Test

Our combination vehicle CDL practice test is graded for you at the end of the test based on the percentage of correct test answers. You will also be able to see user statistics which will show you how many people answered a particular combination vehicle question correctly or incorrectly. Take this practice test until you get a perfect score.



CDL Practice Test (Home) | General Knowledge Test | General Knowledge Test Part 2

True/False General Knowledge Challenge | Hazmat Test | Hazmat True/False Test | Air Brake Test

Air Brake Test (New) | Combination Vehicles Test | Doubles and Triples Test | Tanker Test

Pre Trip Inspection Test | Truck Driver Requirements | School Bus Test | Passenger Vehicle Test

Class A CDL Test #1 | Class A CDL Test #2 | Class B CDL Test #1 | Class B CDL Test #2

CDL Learning Series Tests (New) | Free CDL Training Information

Privacy Policy  |  Contact


© 2017 CDLTEST.co