Police have confirmed that temporary motorway speed limits displayed within a solid red circle are legally binding and enforceable at all times, regardless of traffic levels or the absence of visible construction crews. The clarification comes as millions of drivers navigate smart motorway networks and major roadworks daily, with many questioning whether reduced limits on overhead gantries must be followed when no hazards or workers are visible.
Legal basis for temporary limits
Under Rule 261 of the Highway Code, any speed limit enclosed within a solid red circle is legally binding and enforceable under the Road Traffic Regulation Act 1984. National Highways makes it clear that, whatever the reason for the setting, speed limits displayed within a red circle "will always be enforceable".
The National Police Chiefs' Council (NPCC) also states: "Temporary speed limits, often seen at roadworks or during other events, are legally enforceable by police."
Advisory limits and enforcement
However, advisory speed limits, frequently shown on motorway gantries with flashing amber lights and no red circle, are not legally binding. They are designed to guide drivers through challenging weather or congested traffic conditions.
While many police forces follow NPCC guidance that sets a discretionary threshold (such as 10% plus two miles per hour), officers can legally prosecute drivers for exceeding a limit by just one mile per hour. Disregarding overhead signals is a strict-liability offence that triggers automated enforcement cameras, leading to instant fines and penalty points.
Penalties for speeding
Authorities could treat disregarding amber speed limits as careless driving should it contribute to a collision. Temporary speed limits are enforced by speed cameras, particularly on smart motorways and in roadwork zones. Drivers caught speeding could face a Fixed Penalty Notice (FPN), which may result in a £100 fine and three penalty points on their licence, with the punishment potentially harsher depending on the speed travelled.
