View instructions
Safely pulling double and triple trailers requires knowledge and skill. If you want to pull double or triple trailers, you must add the Doubles/Triples (T) endorsement to your Class A CDL. The Colorado doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The CO CDL doubles triples test covers the following sections of the Colorado CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this CO CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in Colorado.
1. If the engine catches fire, you should:
turn off the engine as soon as you can.
pull into a service station and notify the emergency services.
open the hood as soon as you can.
avoid shooting foam from the vehicle's underside.
2. Which of the following is a reason to cover cargo?
To contain a spill
To protect the cargo from weather
To protect people from spilled cargo
All of the above.
3. It's very important to distribute the cargo so it is:
as high up as possible.
piled up.
in the centre of the load.
as low as possible.
4. When you back under a trailer:
make sure the trailer brakes are locked.
back the tractor slowly.
use lowest reverse gear.
All of the above.
5. Texting while driving a CMV is:
acceptable if the message work-related.
acceptable if the message less than 140 characters.
safer than talking on the phone.
6. When driving a 50-foot truck at 40 mph, your minimum following distance should be:
8 seconds
6 seconds
4 seconds
5 seconds
7. If you are carrying a heavy load that is slowing you down, you should:
keep the vehicle in third gear.
drive in the right lane.
drive on the shoulder.
drive in the left lane.
8. You are driving on a steep downgrade in the proper low gear. Your "safe" speed is 40 mph. When your speed reaches 40 mph, you should:
maintain your current speed, and apply the brakes when you reach 50 mph to gradually reduce your speed to 40 mph.
apply the brakes to gradually reduce your speed to 35 mph, and then release the brakes.
increase your speed to approximately 45 mph, and then apply release the brakes.
apply the brakes to quickly reduce your speed to 25 mph, and then release the brakes.
9. If your vehicle is equipped with air brakes, loss of air pressure in the emergency line will cause:
the trailer emergency brakes to come on.
the springs to put on the brakes.
the vehicle to slide back and forth.
the trailer supply valve to open.
10. Most heavy trucks with manual transmissions require ____ to change gears.
double clutching
single clutching
triple clutching
None of the above.
Page 1 of 2
Next page

CO CDL Doubles Triples Test

Number of questions: 20
Correct answers to pass:16
Passing score:80%
Share This Online CDL Test
Rate this CDL Doubles Triples Test
4.5 out of 5
based on 203 votes