Brake policy briefing: managed motorways

24 January 2014

The Highways Agency is extending the use of managed or 'smart' motorways in the UK, which use technology to monitor and control traffic in response to congestion, bad weather and crashes. Managed motorways include:

  • variable speed limits to reduce maximum speeds and maintain traffic flow in congested periods or bad conditions;
  • CCTV and sensors enabling regional control centres to close, open and change the speed limit of lanes individually to react to conditions or crashes, using overhead signs;
  • and on some stretches, opening the hard shoulder to traffic during busy periods, with emergency refuges provided instead.

The Highways Agency's plans to extend managed motorways now include the introduction of sections with 'all lane running' on parts of the M1, M3, M6, M25, M60 and M62. This means all lanes are open for traffic and there is no hard shoulder at any time for drivers to pull onto in an emergency. Instead, they will have to attempt to leave the motorway or pull into one of the refuge areas that will be provided every 1.5 miles, or onto the verge or even central reservation if this is not possible.

The all lane running proposal differs from existing managed motorways. Most existing managed motorways are either 'controlled motorways', where the hard shoulder is never opened, or use 'hard shoulder running', meaning the hard shoulder is opened to traffic only at busy times.

Brake supports controlled motorways with variable speed limits as they involve close monitoring and control of traffic and reduction of top speeds in busy periods and bad conditions, which has a positive effect on safety. Research has proven lower speeds mean fewer and less serious crashes [1]; a 1% reduction in speed causes a 4% reduction in fatal crashes [2]. Studies suggest that managed motorways deliver safety improvements as a result of the more closely controlled and monitored environment created by regular speed signals and CCTV [3].

However, Brake has serious concerns about the dangers of removing the hard shoulder, especially on a permanent basis through all lane running. The Highways Agency has indicated through the media that it only expects half of people who break down on these all lane running stretches will be able to make it to refuge or off the motorway. Brake is concerned this will leave many people who break down perilously exposed to fast moving traffic. Close monitoring will allow control centres to react to stationary vehicles by closing the lane, but Brake is concerned there will inevitably be a delay before this happens, particularly given indications that not all drivers fully understand and immediately obey lane closure signs. The lack of a hard shoulder could also cause potentially deadly delays in the arrival of emergency service vehicles at crashes.

A managed motorway pilot on the M42, which included hard-shoulder running in busy times, has been credited by the Highways Agency with reducing congestion and reducing crashes by 55.7% [4]. However, as stated above, this is likely due to the variable speed limits and controlled environment, and this pilot differs to what is now being proposed. Refuges are provided much more regularly on the M42 (every 500-800 metres) than is proposed for all lane running motorways, and the hard shoulder is only opened to traffic during busy periods, not round-the-clock as is now proposed. Brake is concerned that the evidence is too limited to show whether the safety gains of variable speed limits and close traffic control are enough to compensate for the possible risks of all lane running [5].

Brake believes the removal of the hard shoulder, temporarily or permanently, risks reducing or cancelling out the improvements in road safety that can be achieved through the other elements of managed motorways. Any crashes or casualties that result from all lane running will not only cause horrendous and needless suffering, but could also negate the economic benefits of managed motorways by causing more motorway closures, which already cost £1 billion per year [6], and by increasing the human and public services costs of crashes and casualties, estimated to be £1.9 million per fatal crash [7].

However, Brake fully supports the rolling out of managed motorways incorporating variable speed limits and traffic monitoring and control, without hard shoulder running, given indications that these measures significantly improve safety as well as traffic flow.

End notes
[1] New Directions in Speed Management: A Review of Policy, Department for Transport, 2000
[2] Managing Speed: Towards Safe and Sustainable Road Transport, European Transport Safety Council
[3] Managed Motorways: Experience from the UK, IBI Group, 2012
[4] M42 MM Monitoring and Evaluation: Three Year Safety Review, Highways Agency, 2011
[5] M42 MM Monitoring and Evaluation: Three Year Safety Review, Highways Agency, 2011
[6] Tackling £1 billion cost of motorway closures, Department for Transport, 2011,
[7] A valuation of road accidents and casualties in Great Britain in 2012, Department for Transport, 2012


Tags: motorways technology smart