Smart motorways have been all over the news recently, with 38 deaths in the last five years bringing them back to the headlines every time.

What is a smart motorway?

A smart motorway is a section of motorway that uses active traffic management to increase capacity, reduce congestion in busy areas, improve journey times, activate warning signs and close lanes. Active traffic management includes using the hard shoulder as a running lane and using variable speed limits to control the flow of traffic.

There are currently three different types of scheme:

  • All lane running
  • Dynamic hard shoulder
  • Controlled motorway

All lane running schemes

This scheme turns the hard shoulder permanently into a running lane, and it’s only closed in the event of an incident. Highways England monitors the traffic via CCTV to manage traffic flow and close a lane if necessary. This type of motorway has overhead gantry signs that will display the speed limit or if a lane is closed.

Dynamic hard shoulder

This type of scheme opens the hard shoulder as a running lane to traffic when the motorway is congested. The overhead gantry displays will tell you if the lane is open and the speed limit.

Controlled motorway

This is where the hard shoulder is never open as a running lane and should only be used in emergencies. The other lanes have variable speed limits that are displayed on overhead gantries.


“Emergency Refuge Areas”, or ERAs, are designed to be safe areas for stranded vehicles on roads without hard shoulders. They appear up to every 1.5 miles on all lane running smart motorways, which means that you will reach a place you can stop in an emergency every 75 seconds on average, if driving at 60mph, according to Highways England.

All new smart motorways going forward will have more ERAs.

They are usually painted orange and are marked by large blue signs with an orange SOS telephone symbol.

Why are they a good idea?

This traffic management technique was first introduced in 2006, enabling smoother traffic flow, more reliable journey times, fewer traffic collisions and reduced noise and emissions.

Highways England said:

“We already have evidence of the benefits that a smart motorway scheme can bring. The first smart motorway scheme (known then as a ‘managed motorway’) opened to traffic on the M42 motorway in 2006. Analysis of data gathered since opening has found that:


  • journey reliability improved by 22 per cent
  • personal injury accidents reduced by more than half.”


Are they dangerous?

The main criticism of smart motorways is that once the hard shoulder is turned into a running lane, there is nowhere for drivers to stop and exit their vehicle safely should they need to. The idea is that once a vehicle has stopped in that lane, Highways England will spot them and close the lane down. However, this can take up to 17 minutes, and relies on other drivers spotting the sign and exiting the lane, with stranded drivers waiting another 17 minutes to be rescued.

Another criticism is that changing the speed limit at short notice will make drivers slam on the brakes, potentially causing accidents. 72,348 people have been fined on so-called smart motorways with variable speed limits in 2017/8.

A government review (ongoing at the time of writing) into the safety of smart motorways was launched after the BBC Panorama’s Freedom of Information request.

The FoI data revealed that on one section of the M25 near misses have increased 20-fold since the hard shoulder was taken away. In the five years before the road was converted into a smart motorway, just 72 near misses were recorded. In the five years following the conversion, 1,485 were recorded.

The findings of the government review are due to be announced shortly, expected to include recommendations to improve the safety of smart motorways such as radar car detection systems that can spot stranded cars as soon as they breakdown.

How to use the existing smart motorways safely

Highways England has offered some quick tips for using a smart motorway:

  • Never drive in a lane closed by a ‘red X’
  • Keep to the speed limit shown on the gantries
  • A solid white line indicates the hard shoulder – never drive in it unless directed
  • A broken white line indicates a normal running lane
  • If your vehicle experiences difficulties, e.g. a warning light, exit the smart motorway immediately if possible and find a place of relative safety to stop

If you’ve broken down:

  • Use an ERA if you’re able to reach one safely
  • If you can’t reach an ERA, switch your hazards on.
    • Try to move on to the verge or at least the nearside lane if it safe to do so
    • If you’re in the nearside lane, exit through the left-hand door and stand away from your vehicle
    • If it’s not possible to get to the nearside lane and exit your vehicle safely, keep your seatbelt on and dial 999