Diversions, closures and speed restrictions
Check this page regularly for the latest updates on road closures, diversions, and speed restrictions
Current closures
A1 southbound weekend closure - 9 to 10 August 2025
We are building a new culvert next to the A1 which will channel water away from the new road.
To work safely, we'll close the A1 southbound between the Black Cat roundabout and Tempsford from 6am Saturday 9 to 6am Sunday 10 August 2025.
Diversion
We'll divert traffic off the A1 at Wyboston onto the A428 towards St Neots. Traffic will then head south along Barford Road and rejoin the A1 at Tempsford.
A1 and A421 weekend closure - 15 to 18 August 2025
We are connecting two new sections of road to the existing network at Black Cat roundabout:
- the new A421 eastbound to A1 northbound free-flow link
- and the new A421 westbound slip road
To work safely, the following closures will be in place from Friday 15 to Monday 18 August 2025 (9pm to 5am):
- A421 eastbound between Cardington Interchange and Black Cat roundabout
- A421 westbound between Black Cat roundabout and Renhold Interchange
- A1 northbound between Tempsford and Wyboston
- Bedford Road between Roxton Road junction and Black Cat roundabout
Diversion
We will divert traffic by the:
- A421 at the Cardington Interchange onto the A603 towards Sandy
- At Sandy, traffic will take the A1 northbound to the Tempsford Interchange
- before exiting onto St Neots Road and joining the A428 at St Neots Traffic will re-join the A1 northbound at the Wyboston junction
A428 weekend closures - August & September
We are connecting the new Cambridge Road, Eltisley, to the A428.
To work safely, the A428 will be closed between Tithe Farm roundabout and Caxton Gibbet roundabout at the following times:
- Friday 29 August to Monday 1 September 2025 (8pm-6am)
- Friday 12 to Monday 15 September 2025 (8pm-6am)
Diversion
We will divert traffic on the A428 towards St Neots joining the A1 northbound at Wyboston Interchange:
- Drivers will leave the A1 at Brampton
- taking the A14 eastbound onto the A1198 Ermine Street towards Caxton Gibbet.
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.
Long term changes
Black Cat roundabout layout change - 8 July 2025
From 8 July 2025, we'll close the northern section of the roundabout
This will temporarily stop road users travelling south on the A1 from the A421.
If you want to travel southbound on the A1, you have two options:
- continue north on the A1 to Wyboston, then loop back southbound.
- exit the A421 at Cardington, take the A603 towards Sandy.
We'll install a concrete barrier on the roundabout to separate A1 southbound traffic from other routes. This will prevent lane changes on the roundabout and help keep traffic flowing safely.
The approach from the A1 northbound remains unchanged.
Black Cat roundabout layout change - 18 August 2025
From Monday 18 August, we will open three new sections of road at Black Cat roundabout, linking in with the existing road network. These are:
- A421 eastbound to A1 northbound free-flow link
- A421 westbound on-slip
- Realigned Bedford Road
A421 eastbound traffic will no longer approach the Black Cat roundabout, instead taking the single-lane free-flow link directly onto the A1 northbound.
The northern section of Black Cat roundabout will remain closed restricting movement from the A421 onto the A1 southbound.
The A1 northbound and A1 southbound approaches to the Black Cat roundabout will remain unchanged.
Let us know what you think
Use our A428 Black Cat to Caxton Gibbet improvements feedback tool to have your say.
This tool features an interactive map, allowing you to click on specific locations to leave targeted comments or provide general feedback.
ECHO is a one-way feedback tool, so if you'd like a response to your feedback you can email the project team at info@a428.co.uk.
Planning diversions, traffic management and speed limits
What you can expect to see
The A1, A421, and A428 will mostly stay open while we carry out our work.
There may be some overnight and full weekend closures from time to time. We'll need these for important tasks like:
- connecting new and existing roads
- building bridges
- delivering large pieces of equipment or materials.
We're committed to being a good neighbour. That’s why we’re carefully planning our work to reduce any disruption to drivers and the local community.
Highest safe speed through roadworks
We’ve determined that a temporary speed limit of 40mph is needed to keep both road users and our workers safe.
This reduced speed limit helps junctions function as usual, which means we won’t need to close roads as often
How we choose diversion routes
We're dedicated to ensuring that any traffic diversions around road closures are safe and appropriate. We'll use diversion routes that can handle the type and amount of traffic being redirected.
The diversion routes will mainly follow major A roads to avoid heavy traffic on local streets. We'll work with local authorities to agree on the best routes.
These diversions are required by law, based on the development consent order (similar to our official approval or planning permission).
To minimise disruption, we will manage traffic carefully, providing clear signs and advance warnings to drivers.
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