Driver's License Test Prep
Pennsylvania Practice Warning Signs

You see a SLIPPERY WHEN WET warning sign. What does the manual tell you to do in wet weather?

Yellow diamond with a black border showing a black silhouette of a car with two wavy skid trails behind its rear wheels.
  1. A.
    Hold the posted limit to avoid slowing other traffic
  2. B.
    Brake firmly before entering the affected stretch
  3. C.
    Reduce your speed and increase your following distance Correct
  4. D.
    Turn on your hazard lights until the sign is behind you
The Why

The answer is "Reduce your speed and increase your following distance"

The manual's instruction for wet weather at a SLIPPERY WHEN WET sign is to reduce your speed and increase your following distance. Choice B tempts drivers carrying over the general 'brake early before a hazard' rule from stopping-distance advice, but the manual specifically warns against quick braking on these stretches because it causes a skid on the slippery surface.

Why the others miss

The traps in the wrong answers

A. Hold the posted limit to avoid slowing other traffic

The manual calls out these stretches as especially slippery when wet, so the posted number is not the target speed for the condition. This answer follows the everyday habit of matching the flow of traffic, treating the posted limit as safe regardless of the warning sign.

B. Brake firmly before entering the affected stretch

The manual says do not brake quickly on these surfaces; hard braking on wet pavement starts a skid. This answer applies the general 'brake hard before a hazard' habit from stopping-distance drills to a surface where the manual specifically forbids quick braking.

D. Turn on your hazard lights until the sign is behind you

The manual's response to this sign is reduced speed and greater following distance, not activating hazard lights. This answer borrows a flasher habit from low-visibility driving and applies it to a road-surface warning sign.

The Rule

This question tests your knowledge of Warning Signs in Pennsylvania. Source: Pennsylvania Driver Manual, "Warning Signs, Slippery When Wet," p.15..

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