Tractors without semi-trailers are referred to as "bobtail tractors." Bobtail tractors are difficult to operate and drivers must exercise caution.

A tractor without a semi-trailer

A tractor with two semi-trailers

A tractor that travels faster than the speed limit

Incorrect coupling and uncoupling of combination vehicles can have extremely dangerous consequences.

Be sure that you are coupling correctly.

You can assume all vehicles are the same.

Be sure that you are coupling correctly.

Cracks in the mounting are acceptable.

To reduce the risk of a rollover when driving a combination vehicle, you should keep the weight of the cargo as low to the ground as possible and drive slowly around turns.

Speed up when nearing a corner.

Take on-ramps faster than the posted speed limit.

Never use the trailer hand valve while parking because doing so may release the air pressure from the braking system, releasing the brakes that are holding the vehicle in place. Instead, use the parking brake or wheel chocks.

Should never be used for parking.

Should always be used for parking.

Should only be used for parking on a downgrade.

Should never be used for parking.

Before a trip, you should ensure that air reaches all air brakes on all trailers by opening up the rear emergency line and service line shut-off valves and listening for escaping air. Close both shut-off valves before beginning to drive.

Close the emergency line valve.

Leave the service line valve open.

Close the emergency line valve.

Combination Vehicles Practice Test | Nebraska 2025 #2 Page 3 of 4

Train for FREE online with our Nebraska CDL combination vehicle test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a NE combination license in 2025, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that DMV requirements for issuing a combination license may vary from state to state.

Number of Question 25

Passing Score 20

Number of Tests 20

Combination Vehicles Practice Test | Nebraska 2025 #2 Page 3 of 4

13 . What is a bobtail tractor?

14 . When coupling:

15 . To prevent a trailer from rolling over, you should:

16 . Before backing your tractor under the trailer, make sure your trailer brakes are:

17 . The trailer hand valve:

18 . Before beginning a trip, you should:

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