This road project has now been completed. This page will be available for 24 months from the date of scheme completion, after which time you will only be able to access this information on The National Archive version of this page.

M25 Junctions 5-7: Smart Motorway

Project status:   Completed

Start date:   May 2013
End date:  Spring 2014

Type:   Major Scheme
help icon

Major Scheme

Part of our programme of improvements (value >10m)

Cost:  £121 million (subject to final accounts)


Where was the project located?

This SMART motorway scheme was carried out on the M25 between junctions 5 and 7 between Sevenoaks and the M23.

Why was the scheme needed?

The M25 is one of Europe's busiest motorways, handling around 200,000 vehicles every day.  It is at the core of our network and is suffering from increasing congestion levels and journey times.  We need to manage traffic flows better and to help achieve this we have already widened the carriageways from 3 to 4 lanes in each direction on the sections between junctions 16 to 23 and junctions 27 to 30.

Since June 2008 we have been considering options to improve the traffic flow from junctions 5 to 7. In January 2009 the Secretary of State decided that this section of motorway could be improved by the introduction of a system to replace the hard shoulder with a fourth running lane (otherwise known as Smart Motorways - All Lanes Running).

*The estimated final cost for this scheme is £129 million.  This figure is subject to final account closures and may result in a variation of this figure.

What work was carried out?

The section of the M25  between junctions 5 and 7 is now running as a "smart" motorway.  The hard shoulder has been converted for use as a permanent traffic lane.  This, together with the introduction of enhanced on-road technology to manage traffic flow will improve the reliability of journey times, providing a boost for businesses and the economy.

The new infrstructure and technology that has been added between junctions 5 and 7 includes:

  • 9 gantries that span both carriageways
  • 10 refuge areas
  • 13 emergency telephones
  • 88 overhead signals
  • 33 verge mounted signs
  • 38 CCTV cameras

How did this benefit road users?

This project will relieve congestion and smooth the flow of the traffic, while maintaining safety and improving journey times. These benefits will also support development in the region.

We already have evidence of the benefits that a smart motorway scheme can bring. The first smart motorway scheme opened to traffic on the M42 motorway in 2006.  Recent analysis of the data gathered since opening has found that journey time reliability improved by 22 per cent and reduced emissions by up to 10 per cent due to traffic flowing more smoothly.

In addition, personal injury accidents have reduced by more than half (55.7%) since hard shoulder running was introduced.  There was also an overall reduction in the severity of accidents with zero fatalities and fewer seriously injured.

Following scheme completion, we undertake a Post Opening Evaluation (POPE) to assess whether the scheme has achieved its anticipated outcomes.  The evaluation is generally carried out at one and five years after scheme opening.  The results of the POPE allow us to learn lessons and improve future scheme delivery.

Learn more about the POPE process.



Part 1 claims for the M25 junctions 5 to 7 Smart Motorway Scheme will be processed by the National Part 1 Claims Team in Bedford. Find out more about Part 1 claims.

How do I find out more information ?

If you have any queries about this project you should contact the Highways Agency Information Line by emailing ha_​info@​highways.​gsi.​gov.​uk or calling 0300 123 5000.

Skanska Balfour Beatty was the contractor for these works.  

Progress to date


We have carried out investigations along the side of the carriageway through the length of the works. 


Archaeological work is ongoing on off site areas.

Publish Environmental StatementAutumn 2010
Site clearanceFrom September 2012
Installation of new concrete barrier in central reservationLate 2012
Start of WorksMay 2013
Completion of work to upgrade the Central Reservation BarrierMid July 2013
Completion of Traffic Management SwitchEarly August 2013
Installation of first new GantryMid September 2013
Completion30 April 2014

Business Case

M25 Junctions 5 to 7 Managed Motorways - Business Case
Business Case - Information correct as at December 2010


M25 Junctions 5-7 Smart Motorway - Smart Motorways Leaflet
M25 Junctions 5-7 Smart Motorway - Get smart know your motorways


M25 Junctions 5-7 Managed Motorways - Newsletter Issue 1
M25 Junctions 5-7 Managed Motorways - Newsletter Issue 1


M25 junction 5 to 7 Final Use Assessment
M25 junction 5 to 7 Final Use Assessment – Noise Insulation Regulations Assessment
M25 Junctions 5 to 7 Managed Motorways - Summary of Consultation Responses
Summary of Consultation Responses Managed Motorways – All Lanes Running M25 J5 to J7
M25 Junctions 5-7 Managed Motorways - Environmental Assessment Report
For a copy of the Environmental Assessment Report for this scheme please email the team at: