Slippery when wet sign
A yellow diamond with a car leaving two wavy skid marks. It warns of a road surface that can become unexpectedly slippery.
How to read it
The MUTCD uses it to warn of unexpected slippery conditions. Pennsylvania's and Michigan's manuals describe the usual case, a surface that becomes especially slippery when wet.
Rules vary by state and country. This explains the sign's standard meaning in the U.S. Manual on Uniform Traffic Control Devices; it isn't legal advice.
Not only rain
A plaque below the sign can give the reason for the slippery surface. The MUTCD lists legends such as ICE, WHEN WET, STEEL DECK and EXCESS OIL.
Read next
- Next in Road signsDeer crossing signA yellow diamond with a leaping deer. It warns of a stretch of road where deer often cross.
- The same shape in Army ranksFirst sergeant (E-8)Three chevrons above three arcs with a diamond between them are the insignia of a first sergeant (1SG), pay grade E-8 in the US Army and the senior NCO of a company.
More road signs
The same shape elsewhere
Browse symbols drawn with curves and waves or diamonds.
Sources
- MUTCD 2009 Edition, Chapter 2C: Warning Signs and Object Markers, MUTCD 2009, Part 2, U.S. Federal Highway Administration, Section 2C.32
- Pennsylvania Driver's Manual, Chapter 2: Signals, Signs and Pavement Markings, Pennsylvania Department of Transportation, p. 15
- What Every Driver Must Know, Michigan driver manual, Michigan Department of State, Chapter 5, sign 52
Researched, edited and approved by Rory Hansen before publishing. Last reviewed September 25, 2026. How we research
Added .