In Partnership with Bradley Public Library

View instructions
Drivers who want to drive combination vehicles must pass the combination vehicles test. The Illinois CDL combination test consists of 20 questions, and you'll need at least 16 correct answers to pass (80%). The test covers the combination vehicles section of the Illinois CDL Manual. Take this practice test now to prepare for the actual IL CDL combination test!
1. Most hydraulic brake failures occur for one of two reasons, one of which is:
loss of hydraulic pressure.
driving in cold weather.
relying too much on the engine braking effect.
excessive downshifting.
2. When inspecting the coupling, make sure ________ between the upper and the lower fifth-wheel.
there are 10 feet
there is no space
there is at least 1 foot
there are at least 36 inches
3. In your mirror, you see a car approaching from the rear. The next time you check your mirror, you don't see the car. If you wish to change lanes, you should:
wait until you are sure the car isn't in your blind spot.
ease into the other lane slowly so the other car can get out of the way.
assume the car left the roadway and change lanes as normal.
None of the above.
4. If the safety relief valve in the air brake system releases air:
this will supply more power to the brakes.
this will supply more power to the drive wheels.
something is wrong.
the valve is fully operational.
5. Which of the following is NOT true? ABS (antilock braking system):
only activates when the wheels are about to lock up.
is required on all truck tractors with air brakes built on or after March 1, 1997.
increases your normal braking capability.
is an addition to your normal brakes.
6. The service line is also called:
control line or signal line.
pressure line or signal line.
signal line or air line.
carrier line or control line.
7. Converter dollies and trailers built before 1975 are not required to have:
emergency brakes.
wet brakes.
lower fifth wheels.
spring brakes.
8. When checking the lights before driving:
you should turn off the engine.
you should check them from inside the vehicle.
the engine must be running.
make sure the parking brake is not set.
9. Why should you cover your cargo?
Because spill protection is a safety requirement in many states.
To protect the cargo from weather.
To protect people from spilled cargo.
All of the above.
10. You are inspecting your vehicle during a trip. What should you do?
Use your senses to check for problems.
Watch gauges for signs of trouble.
Check critical items such as tires, brakes, and lights.
All of the above.
 
Page 1 of 2
Next page

IL CDL Combination Test

Number of questions: 20
Correct answers to pass:16
Passing score:80%
Share This Online CDL Test
Rate this CDL Combination Test
5 out of 5
based on 195 votes