What are smart motorways?


What are smart motorways?   

Considered to be a new age of traffic management, the smart motorway scheme was set to upgrade the UK’s main carriageways and improve traffic flow across the country. However, this project has now been paused for five years. So what exactly are smart motorways and what’s behind the sudden stop in the project? This article will give you all the information you need.

What does the term ‘smart motorway’ mean?

The main difference between smart motorways and normal motorways is the range of technologies used to manage traffic on the carriageway. These technologies include CCTV, radar and sensors that track vehicles moving on the road alongside overhead gantries and information signs that inform drivers of any variable speed limits, lane closures or opening of the hard shoulder. This is in contrast to normal motorways, which have a permanent hard shoulder and a consistent 70mph speed limit.

How do smart motorways work?

Although they all fall under the same term, there are three main types of smart motorways being developed across the UK. All of these manage traffic in slightly different ways:

  • Controlled: these motorways have three or more lanes alongside a traditional hard shoulder that can be used in genuine emergencies. The traffic flow is monitored and, when required, variable speed limits are displayed on the overhead gantry signs and enforced by cameras.
  • Dynamic hard shoulder: again, the traffic on these types of carriageways is managed by a combination of CCTV and overhead gantry or information signs. However, unlike on controlled motorways, the hard shoulder on these can be opened to traffic in busy periods, as indicated by the overhead signs. When this lane is closed to traffic, the sign above it will be blank or have a red ‘X’.
  • All lane running: as the name suggests, this is a type of carriageway where all lanes are used and managed using smart motorway technologies. Variable speed limits or lane closures are indicated by overhead signs. In the place of a hard shoulder, these types of carriageways have emergency refuge areas every one or two miles.

Depending on the design of each motorway, the most appropriate redevelopment was selected to upgrade its traffic management and make vehicle flow more effective.

Why were smart motorways introduced?

With the cost of UK road congestion estimated to be around £2 billion a year and traffic levels only set to increase by 2035, the smart motorway scheme started in 2006 with the aim of improving traffic flow, particularly in busy periods. By using technologies to control which lanes are used and how quickly they’re moving, the aim is to manage high traffic levels effectively without having to invest in widening carriageways or other significant roadworks.

By using controls to keep traffic running smoothly, smart motorways stop drivers from becoming frustrated by start-stop conditions and reduce the build-up of carbon emissions on the carriageway. However, despite these intended benefits, concerns have been raised about the risk smart motorways pose to driver safety, which is why the nationwide scheme has now been paused.

Why has the smart motorway scheme been paused?

Starting with the M42, more than 400 miles of motorways were upgraded before part of the scheme was paused in early 2022 due to concerns over driver safety. While recent data shows that controlled smart motorways were safer for drivers than standard carriageways, the removal of a permanent hard shoulder has been raised as a potential factor in 38 fatalities between 2014 and 2019.

This came after a Transport Committee report made the recommendation to put a pause on the development of these types of smart motorways after its review of the potential safety risks. It’s thought that removing a hard shoulder can leave vehicles stranded in fast-flowing traffic, posing a risk to drivers and passengers and making it difficult for emergency services to reach any incidents.

This means that no new all lane running smart motorways will be created for five years while a reliable data set to fully analyse their safety is collected. Plus, £900 million will be invested in upgrading the safety of existing all lane running motorways, including £390 million which will be spent on installing emergency refuge areas. Despite this slowdown, controlled and dynamic hard shoulder motorways won’t be affected and any findings from the future data set will be fed into their development, meaning new smart motorways will become safer and more effective.

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