What Is a Smart Motorway?

A smart motorway is a section of the motorway that uses additional functions to manage the traffic and reduce congestion so that they can carry more vehicles without restricting the traffic flow.  

You will have seen the work being carried out to transform existing motorways sections into smart motorways and areas such as the M6 junctions 16 to 19 where it is now up and running.

The traffic management methods they utilise are using the hard shoulder as an additional lane, variable speed limits, and close monitoring of closed circuit television (CCTV) systems to ensure these measures are used in a safe manner.

How Do Smart Motorways Work?

Currently there are three different types of smart motorways running in the UK, which are:

  • Controlled motorways
  • Dynamic hard shoulder running schemes
  • All lane running schemes

Each of them work a little differently so we’ve broken down the operation of them below. 

Controlled Motorways

Smart motorways that operate a controlled motorway scheme will have three or more lanes of traffic and an additional lane that remains a traditional hard shoulder. Over the lanes of running traffic there will be a variable speed limit that may be applied.

Where the speed limit is not displayed on overhead gantry signs it will remain at the national speed limit of 70 mph.

Speed limits will be clearly displayed to drivers on the overhead signs at regular intervals, and this can change as you are driving so you should always make sure you are keeping to the speed displayed on the sign you most recently drove past.

The road covered by a variable limit will have speed cameras to enforce the limit at the time, and if caught exceeding this then you can receive a speeding fine. Highways England has advised that there will be a small lag between the limit being implemented and the camera enforcing this limit to accommodate drivers sensibly reducing their speed, though they have not advised how long this will be so we would recommend reducing your speed as quickly as possible whilst remaining safe on the road.

There will also be cameras that are used to monitor the traffic flow on the road and implement the variable speed limit to reduce congestion or slow the impact of additional traffic to a high congestion area.

Dynamic Hard Shoulder Running Schemes

On a motorway that operates a dynamic hard shoulder which means that generally the hard shoulder will remain an area for emergency refuge but when that stretch of road is particularly congested then it will operate as an additional lane for traffic provided there is nobody using the hard shoulder for emergency reasons.

For this type of smart motorway the hard shoulder will still be marked by a solid white line to separate it from the regular lanes of traffic and it will be the overhead signs which indicate whether you are able to drive in it.  

If there is a red X or there is no sign above the lane then it should not be used. In some areas there may be additional messages on larger roadside signs that say “hard shoulder for emergency use only”.

There will also be variable speed limits on these motorways. Again, these limits will be shown on overhead signs and will be changed depending on the traffic congestion ahead. There will be speed cameras monitoring the road as well and capturing anyone speeding above the variable speed limit.

All Lane Running Schemes

An all lane running scheme converts the hard shoulder into a running lane permanently to provide an additional lane for traffic and reduce congestion.

Where an incident occurs the lane will be closed to traffic, and marked so by an overhead sign, just like with a dynamic hard shoulder scheme. This will still be classed as a dynamic hard shoulder.

There are emergency refuge areas spaced regularly along the carriageway for drivers and passengers of a broken down vehicle to use, provided they can safely reach them. Though there is concern that these are not close as possible and the distance was reduced from 1.5 miles to 1 mile in designs created since 2020.

CCTV will be used to monitor these roads for any vehicle in distress and operators will then be able to

Just with the other smart motorways operations, there will also be a variable speed limit on an all lane running scheme as well and speed cameras will be used to enforce this.

What Do Smart Motorway Signals Mean?

We’ve already mentioned a few times the overhead gantry signs which will display your variable speed limits.

However, these signs can also show whether a lane is operational or not. If you look at the image below as well as the variable speed limit you will see that the lane to the far left has a red cross above it.


This lane must not be used, and you should safely move into the next lane of traffic as soon as possible. A lot of the time a lane will be closed due to a vehicle in distress or debris on the road and so by remaining in that lane you could cause further accidents and harm to others and yourself.

 If you do not leave the lane promptly then you will be automatically fined £100 and receive three penalty points on your licence for ignoring the directive.

You might also see a sign with a white arrow directing you to move into a different lane. You should follow this as soon as you are able to as it will usually proceed a lane closure.

There may also be additional signs on the side of the road with the same instructions. We’ve included examples below.


Image Sourced: https://assets.highwaysengland.co.uk/Smart+motorways/Driving+safely+when+you+see+a+red+X+sign.pdf

Xcite Car Leasing Top Tips for Smart Motorway Driving

1. Never drive in a lane closed by a red X

2. Stick to the speed limit shown overhead

3. Don’t speed up until you have passed the gantry showing the new speed limit

4. Don’t cross over a solid white line into the hard shoulder unless signs direct you to

5. If you break down get to an emergency refuge area if it is safe for you to do so and call for help


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