In the United Kingdom, the national speed limit for cars on motorways is 70 mph.
The 70 mph limit applies to cars and many other light vehicles when no lower limit is displayed. It is a maximum legal speed, not a target: drivers must still reduce speed when weather, traffic, visibility, road layout, or an incident makes that necessary.
Motorways can also carry temporary or permanent lower limits. Variable speed-limit systems may display a lower number in a red circle above lanes, and roadworks may impose restrictions for safety. A vehicle’s class and construction can also affect its legal maximum; heavy goods vehicles, buses, cars towing trailers, and vehicles in other categories may have different limits.
The motorway limit is higher than the usual national limit on a single carriageway, which is 60 mph for cars. Local signs always take priority over the national default.