M40/M42 interchange: smart motorway
The M40/M42 interchange is often congested at peak times, affecting both local journeys and long distance traffic between London and Scotland. This interchange upgrade will reduce congestion and delays, improving journey times for motorists. It will also support major new developments in Birmingham, Solihull and the Black Country, boosting economic growth and job creation.
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 M40/M42 interchange upgrade is one of the schemes being paused.
We intend to upgrade the existing central reservation barrier to concrete at the interchange, 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
Our motorway upgrades are carefully planned to provide vital extra capacity where it is needed most and maintain and enhance world-leading levels of safety. At the M40 / M42 interchange we're:
- converting the hard shoulder to create a permanent fourth lane between M42 junction 3 and junction 3a, and M42 junction 3a to M40 junction 16
- installing new emergency areas, with emergency telephones
- installing new electronic information signs, signals and CCTV cameras which will be used to vary speed limits and manage traffic flow and incidents
- installing stopped vehicle detection technology to enhance safety
- upgrading the central reserve with a new reinforced concrete barrier to provide better safety
The M40/M42 interchange is not only important for local drivers but is also a vital link for long distance traffic travelling between London and Scotland.
This scheme aims to:
- reduce congestion and delays
- improve journey time reliability
- maintain a high standard of safety
- support economic growth and job creation
M40 / M42 Interchange Statutory Instrument Consultation (variable mandatory speed limits) - 23 January 2020 to 20 February
Documents

Traffic information
Information about scheduled roadworks and events on our motorways and major roads.Sign up for updates!
Keep up to date with what's happening on this scheme by signing up to our updates.