M3 junctions 9 to 14: smart motorway
We’re upgrading the M3 between junction 9 (Winchester/A34 interchange) and junction 14 (M27 Southampton interchange) to an all-lane running smart motorway. The scheme will link to the forthcoming smart motorway on the M27.
Upgrade paused
On 12 January 2022 the Government’s response to the Transport Select Committee’s inquiry into the roll out and safety of smart motorways was published. It included a commitment to pause the rollout of future all lane running (ALR) smart motorway schemes until a full five years’ worth of safety and economic data is available from upgrades delivered before 2020.
The M3 junctions 9-14 upgrade is one of the schemes being paused.
During the pause, we will continue to make sure all existing ALR smart motorways are equipped with best-in-class technology and resources and are as safe as they can possibly be.
At this location on the M3 we are planning to upgrade the existing central reservation barrier to concrete, which will deliver safety benefits. We are currently planning this work and will share more information as soon as possible.
The rest of the upgrade is being paused until five years of safety data is available.
Project information
Visit our M3 junctions 9 to 14: smart motorway feedback tool to have your say. The tool includes an interactive map. You can click on a location to make a specific comment, or give us your general feedback.
ECHO is a one-way feedback tool, so if you’d like a response to your feedback you can email the project team at: M3J9-14SmartMotorway@nationalhighways.co.uk
The M3 motorway is a key part of the strategic road network and provides a vital economic link from the Midlands (via the A34) and London to the major ports of Southampton and Portsmouth on the south coast (via the M27).
By 2036 this 10-mile stretch of the M3 is forecast to carry at least 20,000 more vehicles a day compared to 2015. We’re converting it into a smart motorway, so it has capacity for these forecast levels of traffic.
It involves changing the hard shoulder into a running lane, adding more signs, deploying variable speed limits from overhead gantries and building emergency refuge areas.
Between junction 9 (Winchester) to 13 (Eastleigh), the M3 will operate four-lanes in each direction. This is known as ‘all-lane running’ and involves the existing hard shoulder being converted into an additional lane for vehicles.
Road users driving northbound and joining the M3 at junction 14 where the roads converge from the M27 eastbound, westbound and from Southampton will see the M3 operate four lanes and a hard shoulder up to junction 13.
For road users driving southbound from junction 13 (Eastleigh) towards junction 14 (Southampton), the road will transition from four lanes with no hard should shoulder and then split into two separate roads to link to the M27 East and West.
The section of the M3 linking to the M27 eastbound will feature two lanes and a hard shoulder. The section of the M3 linking to the M27 westbound will comprise three lanes with no hard shoulder. The road layout into Southampton will remain as it is now.
The section from after junction 13 (Eastleigh) to junction 14 (Southampton) is a variation of smart motorway known as a ‘controlled motorway’.
Documents
Environmental Assessment Report
Environmental Assessment Report - Appendix A Part 1
Environmental Assessment Report - Appendix A Part 2
Environmental Assessment Report - Appendix A Part 3
Environmental Assessment Report - Appendix B Part 1
Environmental Assessment Report - Appendix B Part 2
Environmental Assessment Report - Appendix B Part 3
Environmental Assessment Report - Appendix B Part 4
Environmental Assessment Report - Appendix B Part 5
Environmental Assessment Report - Appendix B Part 6
Environmental summary
Frequently Asked Questions
We expect the work to take about 12 months, the project should be completed during Summer 2023.
The project is budgeted to cost approximately £70 million.
The section of steel barrier between junction 12 and 14 was installed around 1991 and the section through junction 9 to 12 was constructed in about 1995.
Steel barriers have a minimum design life of 20 years but can last much longer when not exposed to harsh weather conditions.
Concrete barriers are much stronger than metal ones and significantly reduce the risk of vehicles crossing over from one carriageway to another, improving safety and reducing the duration of incident-related congestion.
They are virtually maintenance free and will last twice as long as metal barriers, with far less need for closures for routine repairs.
We are sequencing our plans with other schemes in the area:
- M27 junctions 4 to 11 motorway upgrade
Work to upgrade the M27 between junctions 4 and 11 to an all lane running motorway is near completion. We are however holding regular meetings with the M27 project team to co-ordinate planned work and closures, minimising the impact on road users. It is expected, should there be a connection of the temporary traffic management for each project (around M3 junctions 13 and 14), there will not be an increase of additional delays. - M3 junction 9 improvements scheme
The M3 junction 9 improvements project is currently undergoing Development Consent Order planning process. The scheme isn’t due to start until late 2023/early 2024. We are holding regular meetings with the scheme to keep them updated with our project. These meetings will continue throughout the duration of the M3 9 to 14 safety barrier improvements project.
We’ve taken into account and thoroughly studied the environmental aspects of the central reservation upgrade. It has been concluded there will be no significant effects on the environment either during construction or once the central reservation upgrade work has finished.
One of the activities for the central reservation safety barrier improvements work is removing the unintended vegetation and shrubbery growth from within the central reservation.
When removing vegetation, we do so in a manner to eliminate risk to the harming of wildlife. The necessary checks will be undertaken prior to clearance to ensure that animals and birds are identified, and appropriate controls are implemented if required.
We don’t expect our work will be exceptionally noisy. Work will primarily take place during the day. There will be some overnight activities which can’t be done during the daytime, such as temporary traffic management installation.
We do understand that noise from the construction work will be different to what you are used to hearing and may therefore be more obvious.
We’ll be monitoring noise, where possible, during construction. The results will be shared with the Local Authority Environmental Health Officer if required.
Yes – some work will have to be done at night which means we’ll need to close carriageways or slip roads. All closures will be carefully planned to reduce the impact on local roads, clearly signed and approved diversion routes will be in place.
The latest project announcements can be found on this project webpage where you can also register your email address and subscribe to email alerts.
It may appear that work is only taking place on a small section of the road, or at only one end.
During works and closures the workers are entitled to scheduled breaks, as well as having to be briefed regularly by site foremen to ensure safety regulations are understood before carrying out the planned works.
Some of the activities that we carry out can be restricted by poor weather conditions, and work may be temporarily halted as a result. For all these reasons there may be occasions when the workforce is unseen on your travels.
To create the working space for construction to take place, the running lanes need to be altered and narrowed to ensure three lanes are provided. The driving environment around roadworks is likely to be very different to normal. There will be changes to the normal standard of carriageway as well as works vehicles entering or leaving the site. Additionally, excavations, works vehicles and equipment can pose additional risks, and the safety of road users is always our primary consideration.
A reduced speed limit is put in place to give drivers more time to concentrate on this changed environment and reduce collisions. It takes many weeks to install altered lanes with temporary traffic management, so cannot be easily removed.
Neither we, or our contractors, are responsible for any speed enforcements.
If your vehicle has a problem, or you get into trouble on a motorway with roadworks, stay calm and try to exit at the next junction or motorway service area. If you cannot leave the motorway, you should:
- Move over as far left as possible towards the verge
- Put your hazard lights on to warn other drivers and help our control room staff spot you on CCTV. Traffic passing through road works is monitored by CCTV 24/7
- If you are in the left-hand lane and it is safe to do so, exit the vehicle via the left-hand door. Wait behind the barrier if possible
- If you cannot exit the vehicle, do not feel it is safe to do so, or there is no other place of relative safety, remain in the vehicle. Keep your seat belt on and dial ‘999’
Whatever part of National Highways' network you’re driving on, we want you to stay safe and know what to do if anything goes wrong.
Check our Road Safety pages for information about what to do when you see a Red X and driving on motorways.
If you are unable to follow our breakdowns advice for any reason, have stopped in a live traffic lane or feel your life is in danger:
- Stay in your vehicle with your seatbelt(s) and hazard lights on
- Call National Highways on 0300 123 5000 (or 999 if it is an emergency)
- Tell the operator if you are disabled and/or a vulnerable motorist such as an older person or travelling alone
- Keep details of your breakdown provider with you. Your breakdown provider may give you additional instructions in the event of a breakdown.
The emergency services will alert the control room and they will close motorway lanes with Red X(s) and send other help if required, such as a Traffic Officer.
Always carry any medication you need with you and prepare for your journey in advance.
People who are unable to use the emergency roadside phones due to a hearing, speech or physical impairment can contact us via text on 0738 028 3600 for roadside assistance.
We also offer British Sign Language users the SignLive service for getting in touch with our customer contact centre.
Both of these services are available 24 hours a day, every day of the year.’
Find out more about what to do in the event of a breakdown on a UK motorway.
Related Road projects

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