CDL Doubles Triples Practice Test (2024)

1. When you push in the red trailer air supply knob, this will:

disconnect the air lines from the trailer.
open the emergency line shut-off valve at the rear of the last trailer.
supply air to the emergency supply lines.

2. Which of the following is most likely to get stuck on raised railroad crossings?

A single-axle tractor with no trailer
A single-axle tractor pulling a small trailer
A low slung unit

3. Most heavy duty vehicles use ___ air brake systems for safety.

4. You must have at least 4/32 inch tread depth in every major groove on front tires and at least ___ inch on other tires.

5. When possible, you should park:

so you will be able to pull forward when you leave.
on the shoulder.
so you will have to back up when you leave.

6. When driving a 60-foot truck at 50 mph, your minimum following distance should be:

7. Empty trucks:

require shorter stopping distances than fully-loaded trucks.
have better traction than fully-loaded trucks.
may have poor traction.

8. If an aggressive driver confronts you, you should NOT:

9. The last trailer of triples is ______ as likely to turn over as a five-axle tractor.

10. Combination vehicles usually:

are easier to drive than single than single CMVs.
are shorter than single than single CMVs.
require more driving skill than single CMVs.

MO CDL DOUBLES TRIPLES TEST - PRACTICE TEST