National Highways M3 works

National Highways – M3 junction 9 improvements project

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Since mid-July we’ve been working on the M3 northbound verge, carrying out widening works to allow us to move to our next traffic phase. The next phase will move all vehicles into a contraflow system on the M3 southbound so we can carry out major works for the new A34 underpass. We plan to switch the traffic management (safety barriers and signage including temporary speed limit signs) overnight when traffic flows are at their lowest.

From 1 September until the end of October 2025 we will also be removing vegetation from various locations. We understand when it comes to removing vegetation the impact this may have. As part of the project, we’re delivering several environmental enhancements as well as re-planting once works are completed. You can find out more about our chalk grassland restoration here: Chalk Grassland factsheet.

When removing vegetation, we do so in a manner to remove risk to the harming of wildlife. The project has conducted the necessary ecological checks prior to clearance to ensure animals and bird are identified, and appropriate controls are implemented.

The closure needed for these works are detailed below.

Please note overnight on Monday 15 and Tuesday 16 September we are combining works and overnight closures with our colleagues working on road improvements along the A30, between the A303 and the A34 during September. Whilst we appreciate this is a lengthy closure and diversions, it will minimise the overall disruption and need for separate overnight closures.

Overnight closures September 2025 to October 2025

Closures

  • Overnight on Monday 15 and Tuesday 16 September the A34 southbound at Bullington Cross to the M3 junction 9 will be closed (8pm to 6am) – Vegetation clearance and road improvement on the A30, between the A303 and the A34.

This closure will include several slip and linking roads around the Bulling Cross junction the diversion routes are listed below and included on our diversion map link.

  • A34 northbound exit slips at Bullington Cross – A303 east: A34 to Tufton turn around and re-enter the A34 southbound to Bullington to A303 westbound to Barton Stacey to A303 eastbound.
  • A303 eastbound exit slip road – A34 northbound: A303 eastbound to M3 junction 7, turnaround at junction 7 and head southbound to junction 9, exit and join A34 northbound to Bullington Cross.
  • Bullington Cross to junction 9 closure (A34 southbound to junction 9): Bulling Cross to A303 westbound to Barton Stacey to A303 eastbound to M3 junction 7, turnaround at junction 7 and head southbound to junction 9 (to reach Three Maids join A34 northbound).
  • Diversion map link: A34/A33 southbound diversion
  • Overnight on Wednesday 17 September we are closing the M3 northbound between junctions 9 and 8 (9pm to 6am) – Traffic Management switch and Vegetation clearance
  • Overnight on Thursday 18 and Friday 19 September we are closing the M3 southbound between junctions 8 and 9 (9pm to 6am) – Traffic Management switch and Vegetation clearance
  • Overnight on Friday 26, Saturday 27, Sunday 28, and Monday 29 September we are closing the M3 junction 9 southbound entry slip road (9pm to 6am) – Vegetation clearance
  • Overnight on Monday 20, Tuesday 21, Wednesday 22, and Thursday 23 October we are closing the M3 junction 9 northbound exit slip road (9pm to 6am) – Vegetation clearance

Our diversion routes are designed to suit all vehicle types. 

We recommend that you not use a Satnav when following any of our diversions because there is a risk it could direct you down an unsuitable road or back onto our network when it is closed. 

Please remember that closures can change at short notice. You can check the latest information on our daily closures page or find live travel information on ours Traffic England. Our travel alerts give details of live incidents on our network.