As speed of a vehicle increases, the effectiveness of audible warning devices tends to:

• A. Increases
• B. Remains the same
• C. Decreases
• D. Not affected

Answer: (C)

Audible warning devices matter by giving the driver a chance to perceive a threat and begin a safe maneuver. As speed increases, the window of time to react becomes smaller because stopping and avoidance distances grow rapidly with speed. At the same time, wind and road noise rise, which masks or drowns out warning sounds, making them harder to hear. Put together, the warning sound is less likely to be perceived quickly enough to influence behavior at higher speeds, so its overall effectiveness decreases.