Speed limits in Japan

Statutory speed limit in Japan defaults to 100 km/h for divided national expressways and 60 km/h for any other roads, unless otherwise posted. Urban two-way streets are usually zoned at 40 km/h or less.

The highest speed limit in Japan is 120 km/h on sections of Shin-Tōmei Expressway (E1A) and Tōhoku Expressway (E4), and expressways in the Kantō Plain leading to Tokyo.

Summary
The statutory maximum speed limits are 100 km/h on divided national expressways and 60 km/h on other roads. Statutory speed limits for heavy trucks with GVWR over 8 t are 90 km/h, while trailers and three-wheelers are restricted to 80 km/h on divided national expressways. There are no separate urban or rural statutory limits. Urban and rural limits are set by zoning rather than statute.

Implementation of speed limits in Japan can be summarized as:
 * regulatory speed limits of 30 km/h on residential streets and 40 km/h are common for urban two-lane roads.
 * regulatory speed limit of 40 km/h or 50 km/h is common in rural areas due to rugged mountainous terrain.
 * regulatory speed limit cannot be set higher than 60 km/h for any streets with an at-grade intersection, or where pedestrians or cyclists are permitted.
 * undivided expressways have a limit of 70 km/h.
 * variable speed limits are in effect on most national expressways.
 * emergency vehicles are not exempt but have speed limit of 80 km/h on most roads and 100 km/h on divided national expressways, unless higher speed limit is posted. Police vehicles are exempt during speeding enforcement.

Speed camera
A threshold for speed cameras in Japan is set at a minimum of 39 km/h above the limit on an expressway and a minimum of 29 km/h above the limit on other streets, where drivers will face criminal charges instead of traffic infractions. This is due to legal precedents dating back to 1969 restricting police from filming an individual unless a criminal offence is immediately being committed.

Police enforcement
Although there is no official tolerance for exceeding the speed limit, most drivers in Japan tend to drive over the speed limit on major roads. Police enforcement varies depending on the jurisdiction, officers, traffic flow and street types, but 19 km/h above the speed limit on an expressway and 14 km/h above the limit are generally tolerated on other streets.

In 2020, a total of 1,162,420 speeding tickets were issued across Japan, and only 199 tickets were issued for speeding between 0 and 14 km/h over the limit. Of the 199 tickets for speeding 0 - 14 km/h over the limit, Iwate Prefectural Police alone issued 166 tickets. For speeding between 15 and 19 km/h over the limit, Hokkaido, Aichi, Kyoto, Osaka and Fukuoka had the largest shares of tickets issued.

In contrast, Okinawa did not issue any tickets for speeding between 0 and 19 km/h over the limit. Tokyo Metropolitan Police issued a total of 68,693 speeding tickets, but gave out only seven tickets for speeding between 0 and 19 km/h over the limit. Some jurisdictions, such as Tokyo Metropolitan Police, release traffic enforcement locations on their websites.

Speed limit guidelines
There is also a major distinction between surface streets (一般道路) and expressways (高速道路) in terms of speed limit regulations, with different criteria applied for each.

Although some surface streets such as viaducts, trunk and bypass roads are built to expressway standards, many are not legally classified as expressways and are typically distinguishable by the colour of direction signs: surface streets use blue direction signs while expressways use green signs.

Surface streets
Speed limits for surface streets are set within ±10 km/h of the reference speed limit below. Reference speed limits do not apply to expressways.

In Japan, speed limit cannot exceed 60 km/h for any streets with at-grade intersections or where pedestrians or cyclists are permitted. To exceed the 60 km/h threshold, the street must undergo costly grade separation to become a controlled-access highway.

Expressways
Speed limits for expressways are set at 100 km/h or lower speed. The speed limit is set with the lowest "structure compatible speed" (構造適合速度, kōzō tekigō sokudo) criteria below, that is based on design speed in some factors. Unlike surface streets, there is no range limit such as ±10 km/h. Therefore, the speed limit can be modified without limit, but the speed should be "respected".

Intercity expressways typically have higher speed limits, while urban expressways within major cities often have 60 km/h limits and two-lane expressways, typically in rural and remote areas, have 70 km/h limits for simplified division such as guide posts and 80 km/h limits with physical separation.

Most expressways outside of cities have active variable speed limit signs and maximum speeds are lowered according to road conditions such as congestions, accidents, constructions and severe weather. When the statutory speed limits are in effect on national expressways, variable speed limit signs are left blank to indicate the statutory speed of 90 km/h for trucks over 8 t, 80 km/h for trailers and three-wheelers and 100 km/h for other vehicles. Two sets of variable speed limit signs are installed when the regulatory speed exceeds statutory speed of 100 km/h on national expressways or 80 km/h on other roads to regulate the maximum speed of trucks, trailers and three-wheelers to 80 km/h.

Even some 4-lane expressways have 70 km/h speed limit, there is no 90 km/h speed limit although it is allowed.

Speed limits can be set at maximum 120 km/h if it has low crash rates, both the lowest adaptation speed and design speed is 120 km/h, the length is 20 km or more. Other expressways are set maximum 100 km/h including many 120 km/h adaption speed expressways.

lane width (3.5 m ≤ : 120 km/h, < 3.5 m : 80 km/h)

shoulder width (1.75 m ≤ : 120 km/h, < 1.75 m : 80 km/h)