Why the Government Is Considering Cutting the UK Motorway Speed Limit to 60mph

Britain’s 70mph motorway speed limit has been in place since December 1965, a number that predates the internet, the mobile phone, and most of the cars currently on the road. Now, for the first time in decades, that limit is on the table. The International Energy Agency has recommended that the UK and other nations consider cutting motorway speeds as a rapid means of reducing fuel consumption, and the question is no longer a fringe academic proposal. It is a live policy discussion inside government.

The backdrop is the Iran conflict, which began in February 2026 and has pushed unleaded petrol to 157.4p per litre and diesel to 185.73p, the highest levels since 2022. With the Strait of Hormuz, through which roughly 20 per cent of the world’s oil passes, disrupted by the fighting, the IEA has been pressing governments to take demand-side measures that can be implemented quickly without new infrastructure. Cutting motorway speeds, the agency argues, is the fastest and cheapest lever available.

What the IEA Is Recommending and Why

The International Energy Agency’s guidance, published in March 2026, recommended that governments facing supply disruptions consider reducing national speed limits as one of a package of demand-management measures. The IEA’s modelling suggests that cutting motorway speeds by 10mph, from 70mph to 60mph in the UK context, would reduce fuel use by passenger cars, vans, and trucks by a meaningful margin.

The physics behind the recommendation are well established. Aerodynamic drag, which is the dominant force that engines must overcome at motorway speeds, increases with the square of velocity. A car travelling at 70mph faces roughly 36 per cent more drag than the same car at 60mph. In practical fuel consumption terms, most modern petrol and diesel cars achieve around 10 to 15 per cent better fuel economy at 60mph compared to 70mph. At current petrol prices of 157.4p per litre, a driver who averages 40mpg covering 8,000 motorway miles per year would save roughly £53 annually by travelling at 60mph instead of 70mph.

Across the entire UK fleet, the savings would be substantial. The Department for Transport estimates that around 54 billion miles are driven on motorways and dual carriageways annually. Even a conservative 8 per cent improvement in fuel efficiency across motorway journeys would translate into a reduction in fuel demand of roughly 1.5 billion litres per year, worth around £2.4 billion at current pump prices.

The Historical Precedent: Britain Has Done This Before

The last time a British government cut motorway speed limits as an emergency response to an oil crisis was in 1973. When OPEC nations imposed an oil embargo on western countries following the Yom Kippur War, the Heath government introduced a temporary 50mph national speed limit. The measure was unpopular but effective, contributing to a measurable reduction in fuel demand during the worst of the supply disruption.

Other countries have used the same tool more recently. France cut its autoroute limit from 130km/h to 110km/h as an emergency measure during the 2022 energy price shock. Germany, which has no general motorway speed limit, has faced repeated calls to introduce one, though it has resisted. The Netherlands temporarily reduced its limit to 100km/h in 2020 for air quality reasons, a measure that was partly retained permanently.

In the UK, the reduction under discussion is from 70mph to 60mph on motorways only, not on dual carriageways or A-roads. Variable speed limits on smart motorways, which already routinely display 60mph and 50mph during congested periods, would effectively become the permanent limit on those sections. The change would require no new signage infrastructure on smart motorways and relatively modest investment on traditional motorways.

The Political Landscape

The proposal is politically sensitive. Labour has been at pains to distance itself from road use restriction measures since coming to power in 2024, partly in response to the backlash over London’s Ultra Low Emission Zone expansion. Ministers have spoken about protecting working drivers and not imposing extra burdens on people who depend on their cars.

A spokesperson for the Department for Transport said in March 2026 that “no decisions have been made” and that the government was “keeping all options under review” in response to the ongoing fuel price situation. That careful non-committal language has been read by transport analysts as leaving the door open without triggering a political firestorm prematurely.

The AA has stated it would support a temporary reduction if accompanied by clear communications about why it is in place and a firm commitment to restore the limit once the crisis passes. The RAC has taken a similar position, arguing that drivers would accept a temporary measure if the rationale was clearly explained and the change was demonstrably time-limited. The Society of Motor Manufacturers and Traders has noted that modern vehicles are designed for 70mph cruising and that the fuel efficiency gains would be real but modest, and unlikely on their own to shift the strategic supply picture significantly.

What a 60mph Limit Would Mean in Practice

If a 60mph motorway limit were introduced, enforcement would be straightforward. Average speed cameras are already installed on around 2,000 miles of motorway in England, Scotland and Wales. These systems, which calculate average speed between two fixed points, would simply be recalibrated to enforce 60mph rather than 70mph. No new cameras would be required on those stretches.

Journey times would increase. A 200-mile motorway journey at 70mph takes around two hours and 51 minutes. At 60mph, the same journey takes three hours and 20 minutes, an increase of 29 minutes. For professional drivers and freight operators, that extended journey time has commercial implications. For commuters and leisure drivers, the impact depends on whether the journey is almost entirely motorway or includes significant A-road sections.

Safety data would likely improve. Research by the Transport Research Laboratory found that lower speed differentials between vehicles on motorways reduce the likelihood and severity of rear-end collisions. Countries operating lower motorway speed limits consistently record lower motorway fatality rates per billion kilometres travelled than the UK. The current motorway fatality rate of 1.1 deaths per billion kilometres is already the lowest of any road type in Britain, but a speed reduction would be expected to reduce it further.

What To Watch For

The government has not set a timeline for a decision on motorway speed limits. The IEA recommendations were non-binding, and the UK is under no international obligation to act on them. What changes the calculus is whether the Iran conflict persists and whether fuel prices remain at elevated levels through the summer months.

If petrol prices push through 170p per litre or diesel exceeds 200p, the political arithmetic around demand-management measures shifts considerably. At that level, the fuel savings from a speed reduction become large enough to represent a meaningful household benefit rather than a marginal one, and public support for the measure tends to rise with pump prices.

For drivers right now, there is no current legal speed limit change. The motorway limit remains 70mph. If a reduction is announced, it will be signalled with a period of public communication before taking effect, and enforcement would follow with a grace period as drivers adjust. The most practical step for any driver concerned about fuel costs today is simply to set their cruise control at 65mph rather than 70mph on motorway journeys. The fuel saving is real, legal, and available immediately.

Sources:

• Honest John: UK government weighs 10mph speed limit cut to combat oil crisis
• Carscoops: Governments told to lower speed limits to reduce fuel use
• Moovit: UK urged to cut speed limits amid fuel pressures
• RAC Fuel Watch: Latest petrol and diesel prices
• Fuelwise: Fuel duty changes and driver costs