Warning Road Sign (W8-5)
Slippery When Wet Sign Meaning & Driving Rules
The Slippery When Wet sign (MUTCD W8-5) warns motorists that the roadway surface ahead becomes unusually slick and loses tire traction during wet, rainy, or icy weather conditions.
Required Driver Action & Right-of-Way Protocol
Reduce your speed by at least 5 to 10 mph below the posted speed limit. Increase your following distance to 4–6 seconds. Avoid abrupt braking, sharp steering adjustments, and hard acceleration.
Detailed Overview & Purpose
Roadway friction drops drastically when water mixes with accumulated engine oils, rubber residue, and road dust on the asphalt. The Slippery When Wet sign features a diamond yellow design with an icon of an automobile with tire skid marks, symbolizing the loss of directional stability.
The most dangerous driving period is within the first 15 to 30 minutes after rain begins, before the heavy downpour has washed away the slick oil film on the road surface. Braking distances can double or triple, and sudden steering inputs can trigger hydroplaning.
Key Standard & Origin: Bridge decks and overpasses always freeze and become slippery before the rest of the roadway because cold air circulates both above and below the bridge structure, removing heat rapidly.
Where You'll Find This Sign
Installed before bridges, polished asphalt sections, steep downhill curves, shaded forest corridors, and pavement transitions known for reduced wet-weather friction.
Common Driver Mistakes to Avoid
Maintaining full dry-weather cruising speeds in wet conditions. Slamming on the brakes when hydroplaning occurs instead of easing off the accelerator and steering straight.
How This Sign Appears on the DMV Knowledge & Road Test
A guaranteed question on every state DMV exam. Key facts tested: roads are most slippery right after it starts raining, and bridge decks freeze before standard roadway surfaces.
Legal Penalties and Moving Violations
Driving at unsafe speeds for wet conditions violates the Basic Speed Law, resulting in speeding citations and fault in single-vehicle spin-outs.
Sign Variations & Related Types
Bridge Freezes Before Road (W8-13)
Warns specifically that elevated bridge decks freeze earlier than ground pavement in cold weather.
When you encounter the official Slippery When Wet (W8-5) on a roadway, what is your legal duty?
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