Examkin

Question

Difficulty: MediumSpeed and Road Conditions

When a commercial motor vehicle begins to hydroplane across standing water, the driver should immediately apply firm service brake pressure to regain tire grip on the road surface.

Answer: Answer

Answer

False. Drivers must avoid applying the brakes during hydroplaning and instead release the accelerator and hold the steering wheel straight until tire traction is regained.
The statement is false because applying the brakes while a vehicle is hydroplaning removes all directional stability and causes wheel lockup, which can lead to an unrecoverable skid or trailer jackknife. Safe recovery requires easing off the accelerator and avoiding brake application until the tires reconnect with the road surface.

Step-by-Step Solution

1
Identify the traction hazard and vehicle state.
The vehicle is hydroplaning on standing water, meaning a water layer has separated the tire contact patches from the road surface.
Recognizing complete hydrodynamic separation dictates correct control inputs.
2
Analyze the physical effect of applying service brakes during hydroplaning.
Pressing the brake pedal causes the unsupported tires to stop rotating, eliminating gyroscopic stability and inducing a severe skid or jackknife.
Braking on a frictionless water film prevents wheels from rolling and finding traction.
3
Verify standard CDL hydroplaning recovery procedure.
The proper response is releasing the accelerator, depressing the clutch (on manual transmissions), and allowing the vehicle to decelerate smoothly until the tires cut through the water film.
Gradual deceleration without braking preserves directional control.

Key Concept

Hydroplaning mechanics and driver response under adverse wet road conditions
Estimated Time:1m 0s
Rate this question

Topics

Speed and Road Conditions

More questions from this topic