Slippery when wet sign: what it means

Slippery when wet warning sign: a yellow diamond with a black car and wavy skid marks behind it
Drawing: DriveQuiz, based on MUTCD sign W8-5. Simplified; real signs follow the FHWA Standard Highway Signs specifications.

The Slippery When Wet sign warns that the road ahead can be unexpectedly slippery. Slow down and avoid sudden braking or steering.

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Last checked against the sources: · Report a mistake

What it means

MUTCD Section 2C.30: the sign may be used to warn of unexpected slippery conditions. A plaque such as ICE, WHEN WET, STEEL DECK or EXCESS OIL may say why.

Where you see it

Where the surface can be unexpectedly slippery, sometimes with a plaque that explains the reason.

A common mistake

Keeping your dry-road speed and following distance in the rain. Slow down, leave more space and make every move gently.

Quick quiz

What might a plaque under a Slippery When Wet sign tell you?

  1. Why the road is slippery, such as ICE
  2. The speed limit
  3. The distance to a hospital
Show answer

A. Why the road is slippery, such as ICE. Section 2C.30 lists plaques such as ICE, WHEN WET, STEEL DECK and EXCESS OIL. Source: MUTCD 11th Edition, Chapter 2C, Warning Signs and Object Markers: Section 2C.30, FHWA; MUTCD 11th Edition, FHWA

Compare with

Next in warning signs: Deer crossing sign. See all warning signs or the full road signs list.

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Sources

  1. MUTCD 11th Edition, Chapter 2C, Warning Signs and Object Markers: Section 2C.30, FHWA
  2. MUTCD 11th Edition, FHWA. FHWA lists the current version as the 11th Edition with Revision 1, dated December 2025

Sign pictures are our own simplified drawings of the MUTCD designs, which are in the public domain (MUTCD Section 1D.06). Sources and image credits.