Japan Statutory vs Posted Speed Limits (法定速度 vs 規制速度)

Side-by-side comparison

Both are "maximum speeds" (最高速度): limits you must not exceed. The difference is who sets them, how, and when they apply. Article 22 of the Road Traffic Act (道路交通法) says vehicles must not exceed the maximum speed specified by signs or markings where one is specified, and otherwise the maximum speed set by Cabinet Order.

What the statutory limits are (from September 1, 2026)

On an ordinary road with no sign, a car's statutory limit depends on how the road is built (Enforcement Order Art. 11). Roads with a center line (中央線) or marked lanes (車両通行帯), roads where the two directions are separated by a median or barrier, and motor-vehicle-only roads (自動車専用道路) are 60 km/h. All other ordinary roads, the "residential roads" (生活道路) without a center line, dropped to 30 km/h on September 1, 2026 (previously 60 km/h).

Mopeds are 30 km/h on every type of road. Motorcycles (大型・普通自動二輪車) legally count as "motor vehicles" (自動車), so they follow the car numbers, not the moped 30 km/h. Expressway main lanes are 100, 90 or 80 km/h depending on the vehicle; see the expressway page for details.

Emergency vehicles (緊急自動車) have their own statutory limit of 80 km/h on ordinary roads (Enforcement Order Art. 12(3)).

What "the posted limit takes priority" means

If a sign sets a speed, that number is the limit whether it is lower or higher than the statutory one. The National Police Agency (警察庁) explains that a residential road with a 30 km/h statutory limit becomes 40 km/h if a "40" sign is posted, and a 60 km/h road with a "30" sign becomes 30 km/h.

The maximum speed sign is a white circle with a red ring and a blue number. Yellow numbers painted on the road surface (道路標示) mean the same. A sign with a line under the number is a minimum speed sign (最低速度), not a maximum, so don't mix them up.

Why mopeds always get the lower number

The Order on Road Signs, Lane Lines and Road Markings (道路標識、区画線及び道路標示に関する命令) says a maximum speed sign can set a limit for mopeds only at or below the Cabinet Order limit of 30 km/h. The Rules of the Road (交通の方法に関する教則) likewise say mopeds must not exceed 30 km/h, and must not exceed a lower speed when a sign or marking shows 30 km/h or less.

So a moped's limit is "30 km/h or the sign, whichever is lower". A car simply follows the number on the sign, high or low. This is the single most common trick in speed questions.

Real questions from the knowledge test (知識確認)

These are actual items from the menkyopass question set that test this difference.

• "On a road where a sign sets the maximum speed at 40 km/h, a moped may travel at up to 40 km/h." → Answer: FALSE (a moped's limit stays at 30 km/h; take the lower of the statutory and posted limits)
• "On ordinary roads with no speed set by signs or markings, if the road has a center line or marked lanes, the statutory maximum speed for motor vehicles is 60 km/h." → Answer: TRUE
• "On an expressway section where a sign sets the maximum speed, you must follow the posted speed rather than the statutory speed." → Answer: TRUE
• "As long as you stay within the statutory maximum speed, you may drive at that speed regardless of road and traffic conditions." → Answer: FALSE (both are only upper limits; slow down to a safe speed for the conditions)

How to remember it, and practice in your language

Remember: "If there's a sign, follow the sign. If there's no sign, follow the law. Mopeds never go above 30." The 30 km/h residential-road rule started in September 2026, so don't memorize the old line "ordinary roads are always 60 km/h" from older study materials.

The knowledge test has 50 questions in 30 minutes, and you need at least 45 correct. Speed questions are easy points once the numbers are fixed, so use the menkyopass mock test in your language to get used to swapped subjects (car vs moped) and road types (residential vs center line).

Practice questions using this term

• On ordinary roads with a center line or marked lanes where no maximum speed is set by signs or markings, the statutory maximum speed for motor vehicles is 60 km/h.
• The statutory maximum speed for motorized bicycles (mopeds) is 30 km/h.
• On ordinary roads with a center line or marked lanes and no speed limit sign, the statutory maximum speed for large motorcycles is 30 km/h.
• On a road where signs set the maximum speed at 40 km/h, a motorized bicycle (moped) may go up to 40 km/h.
• As long as you stay within the statutory maximum speed, you may drive at that speed regardless of road and traffic conditions.
• When towing a broken-down car with a rope, the statutory maximum speed on ordinary roads is 40 km/h.
• On the main lanes of a national expressway, the statutory maximum speed for light motor vehicles (kei cars) is 80 km/h.
• For a towing vehicle (such as a tractor-trailer) used to tow a broken-down car or similar, the statutory maximum speed on national expressways is 80 km/h.
• On the main lanes of a national expressway, the statutory maximum speed for large trucks is 90 km/h.
• On an expressway section where a maximum speed is set by signs, you must follow the speed on the signs, not the statutory speed.

FAQ

Related guides

• Japan Speed Limits: 60 km/h, 30 km/h Residential Roads, Mopeds 30
• Japan Maximum vs Minimum Speed Signs: The Underline Difference
• Moped vs E-Scooter in Japan: 原付 vs 特定小型原付 Rules
• Japan Expressway Rules: Max 100, Min 50 km/h, Who Can't Enter
• Japanese Road Signs: Common Mistakes in the Conversion Test

Sources (in Japanese)

• e-Gov法令検索「道路交通法」（第22条 最高速度・第23条 最低速度）
• e-Gov法令検索「道路交通法施行令」（第11条・第12条・第27条。令和8年9月1日施行版）
• e-Gov法令検索「道路標識、区画線及び道路標示に関する命令」（別表第一「最高速度（323）」）
• 警察庁「生活道路の法定速度が30km/hになります（令和8年9月1日施行）」
• 警察庁「交通の方法に関する教則の一部を改正する件（令和8年国家公安委員会告示第32号）」（第3章第4節「安全な速度」）