Smart motorways: Everything you need to know

Smart motorways: Everything you need to know

Last updated May 02, 2023

Smart motorways were developed by Highways England (formerly the Highways Agency) to manage motorway traffic flow in busy areas without having to build additional lanes. This helped to reduce costs, disruption, construction time and environmental impact when compared to traditional motorway expansion methods.

One of the key differences between smart and traditional motorways is that smart motorways feature variable speed limits, which are adjusted in real time according to traffic conditions, whereas on conventional motorways, the national speed limit of 70mph applies consistently.

Many smart motorways also remove the hard shoulder, whether permanently or dynamically to improve traffic flow. This feature can ease congestion but has also attracted some criticism concerning safety.

In this guide, we will explain everything you need to know about smart motorways, including what they are, how they work – and what will change following the Government’s recent ‘ban’ on the construction of all new smart motorways.

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How do smart motorways work? 

Smart motorways (known as ‘intelligent transport systems’ in Scotland) utilise a variety of traffic management measures to increase capacity and ease congestion in busy areas on the motorway network, which may include:

  • Variable speed limits, which are adjusted according to traffic conditions.
  • Live warnings of lane closures on overhead signs.
  • Opening the hard shoulder to traffic ‘dynamically’ (in response to congestion levels) or permanently.

The adaptive traffic rules on smart motorways are mandatory. Speed cameras constantly monitor motorists and may issue fines to anyone caught speeding or driving in closed lanes.

Drivers can utilise emergency refuge areas (ERAs) following an accident or breakdown when the hard shoulder is permanently closed or unavailable.

The history of smart motorways

The first smart motorway scheme was successfully trialled in 2006 on the M42, as the hard shoulder was opened to traffic during peak congestion.

Today, there is approximately 375 miles of smart motorway in operation (275 without a hard shoulder), mostly concentrated around London, the West Midlands and the North West of England. Smart motorways account for approximately 10% of the UK’s motorway network.

Which motorways in the UK are smart motorways?

Notable smart motorways include:

  • Large sections of the M25 and stretches of the motorways it crosses including the M23, M3 and M4.
  • The M1 (for most of its length between London and Leeds).
  • Parts of the M62 (near Leeds, Manchester and Bradford).
  • The M6 (through Cheshire, Staffordshire and the West Midlands).
  • Short stretches of the M42 and M5 (near Birmingham).

To see all the currently operational smart motorways, please refer to this map by Highways England.

Are smart motorways safe?

Highways England has stated that journey reliability has improved by 22% and personal injury accidents have been reduced by more than half – and that mile-for-mile, smart motorways are safer than their traditional counterparts.

However, some drivers believe that smart motorways are more dangerous due to the lack of a hard shoulder.

Most criticism of smart motorways relates to ‘all-lane’ and ‘dynamic hard shoulder’ schemes, which remove the hard shoulder on a permanent and temporary basis respectively. Opponents claim that they put drivers at risk of collisions that could have been avoided with a permanent hard shoulder.

This is less of a concern with ‘controlled’ motorways, which do have a permanent hard shoulder.

What has been done to improve their safety?

Highways England has run various communications campaigns to raise awareness on how to use smart motorways safely.

Increasing numbers of emergency refuge areas (ERAs) are now painted in orange to improve visibility – and more signs have been installed to help drivers locate the next available ERA.

The Government and National Highways will also continue with their £900 million investment to make further safety improvements across the existing smart motorway network. This will include the installation of 150 additional ERAs across the network - and improvements to the stopped vehicle detection technology used on every ‘all lane running’ smart motorway.

Government plans to scrap smart motorways explained

On April 15th 2023, the UK Government announced that the construction of all new smart motorways had been scrapped.

The cancellation applies to all planned smart motorway construction, including the 14 previously planned smart motorways (11 that had already been paused and 3 that were scheduled for construction prior to the announcement).

Which planned smart motorways are now cancelled?

11 previously paused:

  • M3 (Junction 9 -14).
  • M40/M42 interchange.
  • M62 (Junction 20-25).
  • M25 (Junction 10-16).

… including the following hard shoulder to ‘all-lane running’ conversions:

  • M1 (Junction 10-13).
  • M4 - M5 interchange (M4 Junction 19-20 and M5 Junction 15-17).
  • M6 Junction 4-5.
  • M6 Junction 5-8.
  • M6 Junction 8-10a.
  • M42 Junction 3a-7.
  • M62 Junction 25-30.

3 previously earmarked for construction:

  • M1 (Junction 10-13).
  • M4 - M5 interchange (M4 Junction 19-20 and M5 Junction 15-17).
  • M1 North Leicestershire.
  • M1 Junction 35A-39 - Sheffield to Wakefield.
  • M6 Junction 19-21A - Knutsford to Croft.

Will any further smart motorway work be carried out?

Although no new stretches of road will be converted into smart motorways, existing smart motorway construction projects on the M56 (Junction 6-8) and M6 (Junction 21a-26) will be completed, given that both projects were over 75% finished at the time of the announcement.

Why were smart motorway plans scrapped?

Public concerns over safety and costs were thought to have influenced the Government’s decision to scrap the proposed smart motorway plans.

Plans to significantly expand the smart motorway network had initially been announced in 2019, with the Government setting out aims to add a further 400 miles of smart motorway by 2025.

However, these plans were ‘paused’ two years later and were set to be reviewed after five years of safety data for smart motorway schemes introduced before 2020 had been collected.

Prime Minister Rishi Sunak pledged to stop the construction of smart motorways entirely during his summer 2022 leadership campaign, before announcing that all future projects had been scrapped in April 2023.

Following the announcement, Transport Secretary Mark Harper also acknowledged the ‘lack of public confidence felt by drivers’ and ‘the cost pressures due to inflation’. (Estimates suggest that the construction of future smart motorways would have cost more than £1 billion.)

What types of smart motorways are there?

There are three types of smart motorway schemes operating in the UK:

‘All lane running’ schemes

On this type of motorway, the hard shoulder has been permanently removed and converted into a ‘running lane’.

This lane is almost always open to traffic and only closed in the event of road incident. (In this case, all lane closures will be signalled by a ‘red X’ displayed on an overhead gantry, a verge mounted sign - or both.)

When you see these sign(s), you must exit the affected lane(s) as soon as possible. Ignoring the ‘red X’ sign is dangerous and illegal.

Speed limits

  • Overhead signs on ‘all lane running’ smart motorways warn drivers of any variable speed limits that are in place. If no speed limit is indicated, this means that the national speed limit applies.
  • Smart motorway cameras can detect vehicles exceeding both variable and national speed limits – or being driven in closed lanes. If caught, you may be issued with a fine and penalty points on your licence. So, drive carefully – and pay close attention to the road!

What to do in an emergency

If you break down or are involved in a road accident on an ‘all lane running’ motorway, you should:

  • Pull into the nearest emergency refuge area (ERA), service station - or leave the motorway at the next exit. ERAs on ‘all lane running’ schemes are spaced an average of 1.5 miles apart – further apart than on ‘dynamic hard shoulder’ smart motorways.
  • Turn on your hazard warning lights (and your parking lights, if visibility is poor).
  • If you have been in an accident, exchange details with the other driver when safe to do so.
  • Contact the police and/or a breakdown recovery service if necessary.

If you cannot use your mobile phone, walk to the nearest emergency telephone on your side of the motorway. Roadside recovery drivers use these as markers to locate broken down vehicles.

If you are unable to take your car off the motorway:

  • Stop in the first lane (if possible).
  • Keep your seatbelt on.
  • Switch your hazard lights on and call 999 for assistance.

‘Dynamic hard shoulder’ schemes

On ‘dynamic hard shoulder’ motorways, the hard shoulder is switched on and off in response to the level of traffic.

A solid white line marks the boundary between the hard shoulder and the regular carriageways - and overhead signage indicates whether the hard shoulder is open.

You must not use the hard shoulder when the signs are blank or display a ‘red X’ (except in the case of emergencies). Look out for variable message signs reading: ‘Hard Shoulder for Emergency Use Only’.

As with ‘all lane running’ schemes, a red X on the gantry means you must exit the lane as soon as possible. Ignoring this sign is dangerous – and if you are caught driving in a closed lane, you risk incurring a fine and receiving penalty points on your licence.

Speed limits

Dynamic hard shoulders feature variable speed limits, which are mandatory – and adjusted in accordance with the traffic conditions.

CCTV systems are used to monitor traffic for any incidents. Any variable speed limits will be displayed on the overhead gantries. If none are shown, this means that the national speed limit applies.

Some drivers expressed concerns that sudden changes in variable speed limits have caused them to brake harshly to reduce their speed in time. However, Highways England have confirmed that there is a short grace period after speed limit signs change before the cameras begin to enforce the new limit.

Although an exact response time for each camera has not been defined, the window can be as short as 10 seconds. Therefore, you should always remain vigilant and respond to changing speed limits safely and in good time.

What to do in an emergency

If you break down or are involved in an accident on a dynamic hard shoulder motorway, you should:

  • Pull into the nearest hard shoulder (if available).
  • Alternatively, pull into the next emergency refuge area, service station or exit.
  • Turn on your hazard warning lights (and your parking lights, if visibility is poor).
  • If you have been in an accident, exchange details with the other driver when safe to do so.
  • Contact the police and/or a breakdown recovery service if necessary.

If you cannot take your car off the motorway:

  • Put your hazard warning lights on.
  • Call 999 for assistance whilst remaining inside your vehicle with your seatbelt fastened.

Only leave your car if it is safe to do so. Leave your car via the left-hand door and wear a hi-vis jacket if you can. Climb over the safety barriers, away from passing traffic and wait for help.


‘Controlled motorway’ schemes

Controlled motorways comprise three or more lanes with variable speed limits, but also include a permanent hard shoulder. According to the Highway Code, you must not use the hard shoulder, except in an emergency – or if you are directed to do so by the police, traffic officers or a traffic sign.

Speed limits

  • As with ‘all lane running’ and ‘dynamic hard shoulder’ schemes, controlled motorways feature gantry signs, which sometimes display variable speed limits. If no limit is displayed, then the national speed limit will apply. There are also cameras in place that enforce the applicable variable or national speed limits.

What to do in an emergency

If your car breaks down or you are involved in an accident whilst driving on a controlled motorway, you should pull into the hard shoulder if it is safe to do so. If you were in an accident, you can exchange details with the other driver and call the police from here.

If you cannot reach the hard shoulder:

  • Try to reach the leftmost lane and get as far off the carriageway as possible.
  • Keep your seatbelt fastened and switch on your hazard lights.
  • Do not exit your car unless you can safely leave the carriageway.
  • Call 999 – and then call a breakdown recovery service if needed.

If you cannot reach the leftmost lane or are unable to leave your car, remain seated inside, with your seatbelt fastened and hazard lights switched on, then call 999.

What are the rules on a smart motorway?

When driving on a smart motorway, always drive in the left-hand lane when the road ahead is clear. Any other lanes should only be used to overtake slower-moving vehicles. Once you have safely passed them, return to the left-hand lane.

What happens when you speed on a smart motorway?

If you are caught breaking the national speed limit (or a variable limit) on a smart motorway, you may receive a £100 fine, in addition to three penalty points on your licence.

However, depending on the severity of the speeding offence, you may receive a fine of up to £2,500 and disqualification from driving.

The ‘red X’ sign

smart motorway red x

What does the ‘red X’ mean?

The ‘red X’ sign is used to warn drivers that a lane is closed when an obstruction (such as roadworks or a broken-down vehicle) lies ahead.

It is important to obey the ‘red X’ sign for the safety of highway workers and any drivers who may have crashed or broken down.

What happens if you ignore the ‘red X’?

If you ignore a ‘red X’ sign on a smart motorway and are caught doing so by a motorway camera, you risk incurring a fine and receiving three penalty points on your licence. However, penalties can sometimes be more severe - and in certain circumstances, you may be summoned to court.

Will I be fined if I ignore the ‘red X’?

If you are caught driving in a closed lane on a smart motorway, you may incur a £100 fine, in addition to three penalty points on your licence.

Smart motorway cameras explained

The HADECS 3 is a sophisticated speed camera that is often seen on smart motorways that can detect when drivers are breaking a national or variable speed limit – or driving in a lane that has been closed.

HADECS 3 cameras are not always painted yellow and therefore are sometimes difficult to spot. If you want to avoid any fines and penalties whilst driving on smart motorways, you should pay close attention to the road - and respond to variable signage appropriately and in good time.

Tips for driving on a smart motorway

  • Do not drive in any lane marked closed by a ‘red X’.
  • Keep to the national speed limit – or the variable speed limit displayed.
  • A hard shoulder is always indicated by a solid white unbroken line. If there is no speed limit displayed above it (or a ‘red X’ is displayed), do not use it, except in emergencies.
  • If you experience issues with your vehicle (e.g. if a dashboard warning light illuminates), exit the motorway immediately, if possible.
  • Put your hazard warning lights on if you break down.
  • Before setting off on any long journeys, check your tyre pressure and tyre tread - and if necessary, change your tyre(s).
  • Don’t forget to check your engine oil (and change it if needed).

If your car is struggling with longer journeys, consider whether it’s the right time to sell your car and make the switch to something more dependable. Why not check out our guide to the best motorway cars to inspire your next purchase?

Emergency refuge areas (ERAs) explained

Emergency refuge areas (ERAs) are positioned up to every 1.5 miles apart. Each ERA has a free emergency telephone, enabling drivers to request assistance. Emergency refuge areas are marked with large blue signs with an orange ‘SOS’ telephone symbol.

If you need to use an ERA, follow the arrows and stop in the marked orange area of the tarmac and switch on your hazard warning lights. You can then use the SOS telephone to speak with a member of the Highways England team who can also contact a breakdown recovery service on your behalf if needed.

You should only use ERAs in the event of an emergency or if you are instructed to do so by the police, a traffic officer or a traffic sign. They should not be used for any other reasons (e.g. to take a break or make a non-emergency phone call).

SoS Phone Sign Illustration

Webuyanycar smart motorway comment

With calls for smart motorways to be scrapped amidst safety warnings, Richard Evans, head of technical services at webuyanycar comments;

“The introduction of smart motorways has meant drivers have new rules to follow whilst travelling on the fastest stretches of UK roads. With our research showing two thirds of drivers (66%) don’t believe that all drivers understand the rules of the motorway, it can make getting around safely a danger for many drivers.

There are three types of smart motorway; controlled, dynamic and all-lane running. The initial objective was to reduce traffic by introducing variable speeds that keep drivers on the move. With the all-lane motorways removing the hard shoulder permanently, it has caused a lot of concern from drivers should they get into trouble as there are no longer emergency refuge areas.

Some smart motorways like dynamic and controlled use variable speeds and introduce the hard shoulder in peak times by using technology to control traffic. Whilst these have more of a place on the road, the concern amongst road users remains high.

Most importantly, drivers need to feel safe getting around on the roads and the introduction of smart motorways has brought a lot of confusion."