What are the two main ways in which drivers select a travel speed?

• A. Vehicle power and transmission settings
• B. Perceptual cues and road message cues
• C. Weather and time of day
• D. Driver age and experience

Answer: (B)

Speed is chosen based on two kinds of information the driver uses: perceptual cues from the surrounding environment and road message cues from the road itself. Perceptual cues are what you notice visually as you move: how quickly objects in the scene are moving toward you (optic flow), the distance and time gap to vehicles ahead, the width and condition of the road, the curvature or grade, and how cluttered or open the roadside looks. These cues help you gauge a safe speed for stopping in time, maintaining a safe following distance, and negotiating bends or slopes.

Road message cues are the explicit signals the road provides: posted speed limits, advisory speeds for curves or work zones, lane markings, signs indicating hazards, and other design features that communicate the expected or required speed. When you see a limit sign or a sharp curve warning, your speed should adjust accordingly to stay within safe margins given the road design.

Together, these cues guide you to select a speed appropriate for current conditions. While factors like vehicle power, weather, time of day, and driver experience can influence speed adjustments, the primary mechanisms for selecting travel speed are perceptual cues and road message cues.