Managed motorways in the United Kingdom

A smart motorway (formerly managed motorway) is a section of motorway in Great Britain that uses active traffic management (ATM) techniques to increase capacity by use of variable speed limits and hard shoulder running at busy times. Benefits include smoother traffic flow, more reliable journey times, fewer road traffic collisions, and reduced noise and harmful vehicle emissions. The term controlled motorway is used for schemes that use variable speed limits without hard-shoulder running (for example, the M25 from J27 to J30).

The technique was first used in the UK on the M42 motorway in the West Midlands in 2006. A higher speed limit of 60 miles per hour (97 km/h) was trialed on the southbound carriageway between junctions 4 and 3A from 2008 (a 10 miles per hour (16 km/h) increase on the previous maximum permissible speed).

In 2007 plans were announced to extend the scheme to two sections of the M6 near Birmingham (4-5 and 8a-10) by 2011 for £150 million. The emergency refuges were to be extended to every 800 metres (0.50 mi) on the roll out. A study into the use of ATM on the M1, M4, M20 and M25 motorways was also announced, however the Department for Transport had decided to proceed with a scheme to widen sections of the M25.

A £2 billion contract was announced to extend the scheme to sections of the M1, M4, M5, M6, M60 and M62 in February 2010 with a further announcement by the new government in October 2010. In March 2012 the government indicated that was considering a trial of higher 80 mph speed limit on some Managed Motorways although proposals for higher speeds on motorways were met with caution on a number of grounds by both motoring and road safety organisations.

Highways England (formerly known as the Highways Agency), Transport NI, Transport Scotland (who promote the technology as Intelligent Transport Systems) and Traffic Wales are responsible for the schemes in England, Northern Ireland, Scotland and Wales respectively. In the following table, schemes are classified into 3 types:

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