Slippery roadJapan
28. Slippery road
A slippery road has reduced tyre grip and can make steering, braking and acceleration less effective. Roads may become slippery because of rain, ice, snow, mud, oil, loose material or other substances on the surface. Drivers should reduce speed, increase their following distance and avoid sudden steering, braking or acceleration. Extra caution is needed in bends, on bridges and wherever the road surface changes unexpectedly.
Wikimedia.org • Charidri • CC0
What can make roads slippery in Japan?
Water, ice, mud, oil or other surface contamination can reduce grip where present. Conditions may change along the road, and a surface that looks clear can still be slippery. Reduce speed for the actual grip and visibility and make smooth steering, braking and acceleration inputs.
🔗 laws.e-gov.go.jp • e-Gov — current enforced Road Traffic Act, revision metadata and full text
🔗 npa.go.jp • NPA — Traffic Lights and Road Signs, official English definitions
🔗 npa.go.jp • NPA — traffic instruction handbook, sign groups and road use; read with current Act
How should you drive on a slippery road in Japan?
Reduce speed early, increase the gap to the vehicle ahead and use smooth steering, braking and acceleration. Do not rely on the posted maximum as a safe target when grip is poor.
🔗 laws.e-gov.go.jp • e-Gov — current enforced Road Traffic Act, revision metadata and full text
🔗 npa.go.jp • NPA — Traffic Lights and Road Signs, official English definitions
🔗 npa.go.jp • NPA — traffic instruction handbook, sign groups and road use; read with current Act
Does a slippery-road warning sign in Japan automatically impose a lower number?
The warning sign highlights a reduced-grip risk; it normally does not itself prescribe a new numerical speed limit. A separate speed-limit sign, temporary restriction or local condition may still apply. Travel below the legal maximum when necessary for safety.
🔗 laws.e-gov.go.jp • e-Gov — current enforced Road Traffic Act, revision metadata and full text
🔗 npa.go.jp • NPA — Traffic Lights and Road Signs, official English definitions
🔗 npa.go.jp • NPA — traffic instruction handbook, sign groups and road use; read with current Act
Warning for a slippery road surface.
English • Traffic sign 209 • Slippery surface. Avoid harsh braking or sudden steering.
日本語 • 209 • すべりやすい。 この先は路面がすべりやすい場所です。急ブレーキや急なハンドル操作を避けてください。
Sources
🔗 Commons.wikimedia.org
🔗 Laws.e-gov.go.jp • 道路標識、区画線及び道路標示に関する命令、別表第一・第二
🔗 Mlit.go.jp • 国土交通省、道路標識一覧
SVG source: Monaneko • Public domain • Original revision 2013-06-19. Wikimedia original unmodified.

Traffic rules
Japan