Radar speed signJapan

An introduction to the traffic rules and road signs of Japan. Learn about driving, road safety and much more in our illustrated book, with answers to frequently asked questions.

For informational purposes only. Always follow official regulations. Some content and images were created with AI assistance.


37. Radar speed sign

A radar speed sign warns drivers that vehicle speeds may be monitored by a fixed camera, mobile radar, lidar or average-speed enforcement system. It reminds drivers to check and respect the applicable speed limit.

The sign does not normally establish the speed limit itself. Drivers must follow the general, posted or variable speed limit applying to the road and must not brake suddenly merely because speed enforcement is indicated.

Radar speed sign
Traffic-enforcement camera. (Okinawa, Japan)
Wikimedia.org • Worldx • CC BY-SA
What should a driver understand from a radar or speed-camera warning in Japan?

A notice warning of speed monitoring is separate from a regulatory speed-limit sign. Obey the applicable road, vehicle and posted maximum regardless of whether equipment is visible. Do not infer the exact equipment, coverage or a legal duty to provide a warning from a camera pictogram alone.

🔗 laws.e-gov.go.jp • Japan Road Traffic Act — Articles 7–9, 17–43, 44–45 and 70: actual controls and safe circulation

🔗 laws.e-gov.go.jp • e-Gov — current enforced Road Traffic Act, revision metadata and full text

Which speed limit applies when a radar warning is displayed in Japan?

Follow the speed-limit sign, applicable speed zone or statutory road and vehicle limit. A camera symbol or enforcement notice must not be mistaken for a sign raising or ending that limit.

🔗 laws.e-gov.go.jp • Japan Road Traffic Act — Articles 7–9, 17–43, 44–45 and 70: actual controls and safe circulation

🔗 laws.e-gov.go.jp • e-Gov — current enforced Road Traffic Act, revision metadata and full text

Should you brake abruptly when you notice a radar sign in Japan?

No. Adjust to the lawful and safe speed smoothly, leaving adequate space behind and ahead. Enforcement information does not authorise sudden unsafe manoeuvres or stopping to inspect the camera.

🔗 laws.e-gov.go.jp • Japan Road Traffic Act — Articles 7–9, 17–43, 44–45 and 70: actual controls and safe circulation

🔗 laws.e-gov.go.jp • e-Gov — current enforced Road Traffic Act, revision metadata and full text

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