FREE CDL Combination Vehicles Practice Test Online | Colorado 2024
Train for FREE online with our Colorado 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 CO combination license in 2021, 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.
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1 . Before backing your tractor under the trailer, make sure your trailer brakes are:
Dry.
Correctly following the steps to couple and uncouple trailers is vital to safely operating a combination vehicle. Before backing your tractor under the trailer while coupling, make sure your trailer brakes are locked.
2 . Using the trailer hand brake while experiencing a trailer jackknife will:
Continue the skid.
If you are experiencing a trailer jackknife, you can help your tires regain traction by releasing the brakes. Using a trailer hand brake while experiencing a skid will only cause the skid to continue.
3 . Rollovers happen when drivers:
Drive illegally.
A rollover happens as a result of a driver taking a turn at too high a speed. Be sure to take turns and curves safely and slowly.
4 . An air supply control lever should be in its "normal" position when you are:
Using your spring brakes.
Tractor protection controls in older vehicles may be operated by levers instead of knobs. If an air supply control is set in its "normal" position, it is properly set for you to pull a trailer.
5 . Fully-loaded rigs:
Should not be driven.
Because the weight of cargo gives them a higher center of gravity, fully-loaded rigs are 10 times more likely to roll over in a crash than empty rigs.
6 . What is a tractor protection valve?
A valve that prevents the trailer from accidentally being released
In a combination vehicle with air brakes, the tractor protection valve keeps air in the tractor or truck brake system in the event of the trailer breaking away or developing a leak.
7 . Simply changing lanes can cause:
Other drivers to reduce their speed.
