A43 Traffic Moves onto New Bridge Above the HS2 Route

Traffic on the A43 near Brackley now runs across a newly completed bridge, clearing the way for excavation of the cutting that will carry HS2 trains beneath the road.

Both carriageways now cross the HS2 A43 bridge

HS2 Ltd completed the traffic switch⁠ in two stages: the northbound carriageway moved onto the bridge during 11–12 July, followed by the southbound carriageway on 18–19 July. The A43 reopened in both directions on Sunday evening after the second weekend closure.

The road connects Oxford, Brackley and Northampton, provides access to Silverstone and links the M40 with the M1. The final closures were scheduled after the British Grand Prix at the beginning of July to reduce disruption during the event.

Top-down construction moves below the road

Preparatory work began in 2023, when engineers temporarily realigned the A43 to create an island between the carriageways for bridge construction. The structure rests on piled foundations sunk 52 metres deep, while seven steel beams support the 66-metre concrete deck carrying the road.

The beams were installed during three weekend closures⁠ in March 2025 using a 750-tonne crane. After the deck and road surface were completed, each carriageway was diverted across the bridge in turn while traffic continued in the opposite direction.

With vehicles now travelling above the structure, crews can excavate the cutting and remove material beneath the road. This will create the space needed for the high-speed railway to pass under the A43.

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The bridge forms part of an 80-kilometre section around Brackley being delivered by EKFB, the joint venture of Eiffage, Kier, Ferrovial Construction and BAM Nuttall, working with ASC. National Highways and Kier Transportation also supported the road realignment and traffic management.

HS2 says six smaller roads and bridges across Buckinghamshire and Northamptonshire have reopened to local traffic during the last six months. Across the wider railway project, more than 500 bridging structures range from footbridges and culverts to green bridges, motorway crossings and the Colne Valley viaduct.

HS2’s latest programme update⁠ states that civil engineering between London and Birmingham is about two-thirds complete. First services from Old Oak Common to Birmingham Curzon Street are expected between May 2036 and October 2039, while the full scheme including Euston and Handsacre is estimated to open between May 2040 and December 2043.

At the A43 site, the immediate next stage is excavation and earthworks beneath the live road.

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