Diversions, closures and speed restrictions
Check this page regularly for the latest updates on road closures, diversions, and speed restrictions
Current closures
14 to 17 November 2025 - A1 southbound weekend closure
We're changing the road layout at Black Cat roundabout.
Closure
We'll close the A1 southbound between Wyboston and Tempsford from 9pm Friday 14 to 5am Monday 17 November 2025.
A1 southbound diversion
- leave the A1 at Wyboston and east on the A428 towards St Neots
- take the exit onto Barford Road towards Tempsford
- re-join the A1 at Tempsford
21 to 24 November 2025 - A1 northbound, A421 westbound and Bedford Road weekend closure
We're changing the road layout at Black Cat roundabout.
Closures
From 9pm Friday 21 to 5am Monday 24 November 2025, we'll close:
- A1 northbound between Tempsford and Black Cat roundabout
- A421 westbound between Renhold and Black Cat roundabout
- Bedford Road in both directions between Roxton Garden Centre and Black Cat roundabout
A421 westbound diversion
- travel south on the A1
- take the A603 towards Bedford
- re-join the A421 at Cardington interchange
A1 northbound diversion
- leave the A1 northbound at Tempsford
- head north on Barford Road towards St Neots
- re-join the A1 northbound at Wyboston.
17 to 21 November 2025 - A1 northbound and A421 eastbound overnight closures
Anglian Water is installing a new connection to the water main near the A1 carriageway.
Closure
We'll close the A1 northbound between Black Cat roundabout and Wyboston, and the A421 eastbound between Renhold and Black Cat roundabout from Monday 17 to Friday 21 November 2025 (9pm to 5am).
Diversions
A1 northbound diversion:
- exit the A1 at Tempsford onto St Neots Road towards St Neots
- take A428 exit re-joining the A1 at Wyboston
A421 eastbound diversion:
- exit A421 at Cardington Interchange onto the A603 towards Sandy
- at Sandy, join the A1 northbound
- exit the A1 at Tempsford onto St Neots Road towards St Neots
- take A428 exit re-joining the A1 at Wyboston
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 - 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.
Black Cat roundabout layout change - 24 November 2025
From Monday 24 November, we'll open new sections of road at Black Cat roundabout, linking with existing road networks.
A1 southbound
We’re moving the A1 southbound onto a new stretch of road passing under the new east bridge at Black Cat roundabout.
Make sure you’re in the correct lane before you reach the junction:
- left hand lane for A1 south, A421 or M1
- right hand lane for A1 north, A421 or M1
A1 northbound
We’re moving the A1 northbound approach onto the new northbound on-slip at Black Cat roundabout.
Make sure you’re in the correct lane before you reach the junction:
- left hand lane for A421 west and Bedford Road
- right hand lane for A1 north
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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