Practice question

Why are chocks critical for a trailer without spring brakes?

They keep ABS active
Air can leak away and release air-held brakes
Chocks increase power
They replace kingpin

Answer: B — Air can leak away and release air-held brakes

The correct answer is shown above. Try the full quiz for additional practice.

Practice more: Iowa CDL Combination Vehicles Test Practice Questions - Iowa Commercial Driver License Combination Vehicles Test Exam →