We are replacing the Power Road Bridge as part of our programme to improve London's roads and public spaces.
The bridge, which was built in 1922, has reached the end of its operational life and is beyond simple repair. Not replacing the bridge would mean permanent closures of footway and cycle tracks, lane closures and restrictions on the type or weight of vehicles that use the bridge.
The new structure replacing the existing bridge has been designed to last at least 120 years.
The new bridge will have improved footways, lighting and better facilities for cyclists on the western side, making this section of the A406 safer for all users.
The main highway works are nearing completion on Power Road Bridge, and all four lanes of the A406 North Circular will reopen on 22 November 2018, as planned.
Construction activity will continue on the Power Road Bridge replacement into 2019 while we finish rebuilding footways, cycle tracks and verges on both sides of the road.
We are rebuilding the new road, kerbs, pavements, cycle tracks and verges on both sides of the road.
We will also finish work to the underside of the bridge and railway embankments - this may not be visible from street level.
Final works, including re-opening the pavements and cycle routes across the bridge, are scheduled for summer 2019.
The A406 Gunnersbury Avenue is open in both directions.
A temporary 30mph speed restriction is in place between the Chiswick Roundabout and Park Place Drive.
Check live traffic news before you leave to stay up-to-date and avoid disruption to your journey.
Get the latest travel information by following @TFLTrafficNews on Twitter.
Bus route 440 serving Stop D (Power Road) may be affected by increased traffic in the area surrounding Power Road.
Check live bus service updates before you leave.
Get the latest updates by following @TfLBusAlerts on Twitter.
Access for pedestrians and cyclists will be maintained across the bridge at all times. Any temporary changes will be clearly signed.
The service bridge has been converted into a temporary footbridge which pedestrians and cyclists can use to cross the railway. For the safety of both cyclists and pedestrians, cyclists must dismount and walk across the temporary footbridge.
Normal working hours are 07:00 to 19:00 on weekdays and Saturdays. Some works will take place on Sundays and Bank Holidays. All working times are agreed with London Borough of Hounslow.
To reduce noise, vibration and disruption during the works we are using a range of measures including:
We will also have recycling skips on site to ensure we recycle everything we can.
Local residents and businesses will be updated about the works.
We are working closely with Network Rail, the London Boroughs of Hounslow and Ealing and the emergency services to minimise disruption and ensure the works proceed as safely, efficiently and as quickly as possible.