Home › CDL Practice Tests › General Knowledge Questions › Question 83
When should engine retarders be turned off?
- A.On dry pavement at highway speed
- B.Only in tunnels
- C.Whenever they are installed, they are never useful
- D.When the road is wet, icy, or snow-covered, because they can cause the drive wheels to skid
Correct answer
D. When the road is wet, icy, or snow-covered, because they can cause the drive wheels to skid
Why
Retarders brake only the drive wheels, and on a slick surface that one-sided force can lock or slide those wheels and start a jackknife. Use them on dry roads and switch them off when traction is poor.
Manual topic: Safe Driving - Skid Control · From the General Knowledge practice bank (GK-083).