Diversions, closures and speed restrictions
We're trying to minimise road closures and keep traffic flowing as much as possible while the improvements are carried out. Stay up to date with diversions, road closures and current restrictions on this page.
While it won't always be possible to completely avoid some short-term delays and congestion, we have looked at lots of different scenarios and outcomes to keep open as many lanes as we can. We are working closely with local authorities to keep traffic moving as much as possible during construction.
What you can expect to see:
The A1, A421 and A428 will mainly remain open for the duration of the works.
There will be occasional overnight closures and full weekend closures, when we'll need to connect the new and existing roads, build bridges, and unload sizeable items of equipment or materials.
We're committed to being a good neighbour - so we're working hard with our contractors to plan and phase the construction, to really minimise impacts to all road users and the local community.
Current closures
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 our Traffic England site. Our travel alerts give details of live incidents on our network.
Overnight closures on A1 - October 2024
We are undertaking essential electrical site clearance on the A1.
Closure
To work safely, we'll close the A1 northbound overnight at the following times:
- Monday 28 to Wednesday 30 October, 9pm to 5am (A1 northbound between Black Cat roundabout and Wyboston)
- Wednesday 30 October to Friday 1 November, 9pm to 5am (A1 northbound between Sandy and Black Cat)
Diversion
A1 northbound between Black Cat roundabout and Wyboston: Traffic diverted onto A505 at Baldock to join the A1198 at Royston, then west on A428 at Cambourne where they can rejoin the A1 northbound at Wyboston via St Neots.
A1 northbound between Sandy and Black Cat: Traffic diverted onto the A603 at Sandy to join the A421 at Cardington and then towards the Black Cat roundabout.
Overnight closure of Bedford Road - Monday 7 October
We are undertaking essential electrical site clearance on Bedford Road.
Closure
To work safely, we'll close between Black Cat roundabout and Roxton Garden Centre on Monday 7 October from 8pm to 5am
Diversion
Traffic will be diverted from Black Cat roundabout - along the A421 westbound towards Bedford. Leave A421 at Renhold and continue on St Neots Road, Bedford Road, and Roxton Road.
Traffic from Roxton Road bridge will use the same diversion route in reverse.
Overnight closures on A1198 Ermine Street South - October 2024
We are undertaking essential utility diversions and the installation of a temporary concrete safety barrier on the A1198 at Caxton Gibbet.
Closure
To work safely, we'll close the A1198 Ermine Street South at the following times:
- Monday 14 to Saturday 19 October, 8pm to 6am
- Monday 21 to Saturday 26 October, 8pm to 6am
Diversion
Traffic will be diverted along the A428 towards St Neots, before taking the B1040 St Ives Road and rejoining the A1198.
The diversion route will take appoximately 5 minutes.
A1198 Ermine Street South diversion map.
Weekend closure of A421 - November 2024
We are installing six large steel beams on the new Roxton Road bridge. Each beam is 37 meters long and weighs 130 tonnes. This is a crucial step in the build process as the beams will support the weight of the bridge deck, where cars and people will travel.
Closure
To work safely, we'll close:
- the A421 in both directions between the Renhold junction and the Black Cat roundabout
- Roxton Road bridge (including pedestrian access)
at the following times:
- 9pm Friday 1 to 5am Monday 4 November 2024
- 9pm Friday 8 to 5am Monday 11 November 2024
Diversion
Eastbound traffic diverted via the A603 at Cardington to A1 northbound at Sandy to Black Cat roundabout.
Westbound traffic will use the same diversion route in reverse.
Longer term closures
As part of our work to construct the new Roxton Road link road, we need to relocate some utility services. This includes relocating a watermain on The Lane in Wyboston. To get this done safely, we'll need to temporary close The Lane from Monday 2 September 2024. We expect the work to be completed and the road reopened by October 2024.
During this time, your water supply won't be affected, and residents on this stretch will always have access to their homes.
Diversion
Travelling from The Lane: Road users will be diverted west along The Lane and then south down Roxton Road until they reach the junction with Bedford Road. Road users will then head east towards the Black Cat roundabout.
Travelling towards The Lane: Road users will be diverted east along Bedford Road and then north up Roxton Road until they reach the junction with The Lane. Road users will then head east down The Lane.
In January 2024, we made a temporary switch to the road layout at the Black Cat roundabout as we began work to upgrade the junction. This temporary layout has allowed traffic to continue to pass through the roundabout smoothly - removing the need to close any part of the road permanently.
The current road layout will be in place until spring 2025.
Please be assured that we take your feedback extremely seriously and have been monitoring the area constantly since implementation. We monitor via live CCTV, as well as multiple daily visits to site at various times of the day, in daylight as well as in the dark.
Cycle, pedestrian and horse rider route closure, Caxton Gibbet
As part of our work, we need to close the cycleway, pedestrian and horse rider route (73/17) just north of the existing roundabout.
While these works take place, cyclists, pedestrians, and horse riders will be directed along a diversion route, running eastward along the A1198 Ermine Street, avoiding our worksites and rejoining the road at Brockley Road.
We estimate the diversion will make journeys longer by:
- 5 minutes for cyclists
- 15 minutes for walkers
An upgraded route will open to cyclists, pedestrians, and horse riders in spring 2027.
Temporary closure of Cambridge Road (Eltisley) - 27 August 2024 to Spring 2025
As part of our work to upgrade Eltisley junction, we need to divert utilities and raise the level of the existing road.
To do this safely and efficiently, we'll need to close Cambridge Road for an extended period of time from Tuesday 27 August 2024.
We expect the work to be complete and the road reopened by spring 2025.
Diversion
Travelling from the A428
Traffic will be diverted along west of the A428 and then south onto the B1040 and east into Eltisley on the St Neots Road.
Travelling from The Green
Traffic will be diverted east out of Eltisley along St Neots Road, then north onto B1040 to the A428.
Permanent closure of A1 access from Chawston Lane - 30 August to Spring 2025
On Friday 30 August 2024, we'll permanently close the access to and from the A1 on Chawston Lane.
This will allow us speed up construction of the new Roxton Road link without multiple road closures.
The new link road is expected to be complete in spring 2025.
If you live on Chawston lane, you will still have access to your property. However, you will need to follow the dedicated diversion route.
Diversion
Travelling from Chawston Lane
Traffic will be diverted south down Roxton Road until it reaches the junction with Bedford Road. Road users will then head east towards the Black Cat roundabout or west towards Roxton village.
Travelling towards Chawston Lane
Traffic will be diverted north up Roxton Road until it reaches the junction with Chawston Lane.
Planning diversions, traffic management and speed limits
We've monitored traffic volumes at 24 different locations ahead of construction. We'll continue monitoring it throughout construction.
Highest safe speed
We've assessed that a 40mph temporary speed limit is necessary to protect road users and our workforce.
The temporary speed limit allows junctions to operate at their normal capacity. This means we'll need fewer full road closures.
Carriageway and slip road closures
We've planned our work to keep road closures, diversions and road layout changes to a minimum.
As far as possible, we'll only use closures for for essential works, like demolition or major phasing changes.
We'll use static narrowed lanes and temporary alignments to maximise working space. This will help us keep the number of full closures as low as possible. For example, we'll keep two lanes open on the A421 eastbound when we start construction.
Later in construction, we'll use some of the newly constructed slip roads to keep the traffic moving. We'll use slip roads and link roads to create a temporary ‘large gyratory’ at the Black Cat while we build the new A1 underpass.
How we choose diversion routes
We're committed to giving you safe and suitable diversions around closures. We'll only use diversion routes that can take the type and volume of traffic that's being diverted.
Diversion routes will stick to major A roads on our road network, minimising rat running on local roads. We'll agree diversion routes with the relevant local authorities.
We must follow the diversions set out in the development consent order (which is like our planning permission).
We'll reduce disruption by managing traffic with clear signs and advance warning.
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