View instructions
Drivers who want to drive combination vehicles must pass the combination vehicles test. The Idaho 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 Idaho CDL Manual. Take this practice test now to prepare for the actual ID CDL combination test!
1. To prevent a rollover, you should keep the cargo as close to the ground as possible and:
go slowly around turns.
keep an eye on your tires.
keep the vents clear so they work correctly.
2. To test the tractor-semitrailer connection for security:
plug the electrical cord into the trailer and fasten the safety catch.
pull out the air supply knob.
check that the trailer is locked onto the tractor by pulling the tractor gently forward while the trailer brakes are still locked.
3. When you are uncoupling a loaded trailer, lower the landing gear until:
the tractor frame is under the trailer.
makes contact with the ground, and leave the trailer off the fifth wheel.
it makes firm contact with the ground.
4. If the ABS is not working:
you still have normal brake functions.
the vehicle will have no brakes.
the vehicle will have weak brakes.
5. 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:
assume the car left the roadway and change lanes as normal.
ease into the other lane slowly so the other car can get out of the way.
wait until you are sure the car isn't in your blind spot.
6. Do NOT use the parking brakes:
when you park for less than two hours.
when you leave your vehicle.
if the brakes are very hot.
7. When driving with cargo, you should re-check the cargo and securing devices as often as necessary to keep the load secure, and inspect again:
every 3 hours or 150 miles.
every day.
every 6 hours or 300 miles.
8. Fully loaded rigs:
are much more likely to roll over than empty rigs.
are just as likely to roll over as empty rigs.
are less likely to roll over than empty rigs.
9. If you try to couple when the trailer is too low:
the tractor could roll away.
the tractor may strike and damage the trailer nose.
it might not couple correctly.
10. You have uncoupled a trailer and want to inspect the landing gear. The tractor should be positioned:
with the tractor frame above the trailer.
completely clear of the trailer.
with the tractor frame under the trailer.
Page 1 of 2
Next page

ID 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 238 votes