Costain has completed critical works for Transport for London (TfL) as part of the A40 Westway Structures Refurbishment project.

The work saw Costain install seven expansion joints on the A40 between Wood Lane and the Marylebone Flyover, which is used by 96,000 vehicles each day.

The section of the elevated A40 spans approximately 4.5km through the London boroughs of Kensington and Chelsea, Hammersmith and Fulham, and the City of Westminster. The bridge structures that support the carriageway and slip roads were built more than 50 years ago using reinforced concrete and, due to variable weather conditions, required major maintenance to keep the road network running.

 Costain has replaced seven joints on the bridge structures and slip roads, and has carried out concrete repairs, resurfacing and ancillary works to improve safety and reliability. As part of a previous package of works, Costain also replaced an additional critical roller expansion joint on the A40 Westway.

In 2026 Costain is due to commence the next package of work on the A40 Westway Structures Refurbishment project, which will see it deliver additional improvements and maintenance upgrades at the Marylebone Flyover and on the A40 Westway.

Emma Curran, senior project manager at Costain, commented: “The A40 is one of London’s busiest routes and vital to regional prosperity and economic growth. Our upgrades have extended the lifespan of this section of the A40 by more than 50 years, and thanks to our close collaboration with TfL and the application of production-thinking principles, we ensured minimal disruption to residents and road users.

 “We’re looking forward to progressing to the next package of works, maintaining our high standards of safety, quality and best-in-class delivery, to further improve the resilience of London’s road network.”

Charlotte Day, project manager at TfL, said: “The A40 Westway is a critical transport artery into the nation’s capital that has required essential maintenance works. Costain and its supply chain has worked efficiently and innovatively to replace the joints that will ensure the road can continue to run safely and reliably for years to come. This has all been achieved with the least disruption possible to people using the road and living in the area.”

Costain and TfL are also improving the reliability and safety of London’s road network by working to renew the Gallows Corner Flyover, the strategic link that enables access to the M25.