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
A428 weekend closure - June 2025
We are connecting the A428 with the new Cambridge Road junction at St Neots.
To work safely, the A428 between Tithe Farm roundabout to Caxton Gibbet roundabout will be closed from 8pm on the following dates:
- Friday 6 to 6am Monday 9 June 2025
- Friday13 to 6am Monday 16 June 2025
Diversion
We will divert traffic along the A428 towards St Neots / A1 then continue north on A1 to Brampton Hut. Return on A1 southbound to join A14 eastbound, leave the A14 at A1198 Ermine Street and follow diversion signage along A1198 to Caxton Gibbet roundabout.
A428 between Tithe Farm roundabout to Caxton Gibbet roundabout - 2 to 6 June 2025
Closed overnight (8pm to 6am) while we prepare to open the new Cambridge Road junction at St Neots.
Diversion
We will divert traffic along the A428 towards St Neots / A1 then continue north on A1 to Brampton Hut. Return on A1 southbound to join A14 eastbound, leave the A14 at A1198 Ermine Street and follow diversion signage along A1198 to Caxton Gibbet roundabout.
A428 Eltisley weekend closure - May 2025
We are connection the new stretch of A428 to the new northern roundabout at Caxton Gibbet.
To work safely, the A428 will be closed in both directions between Eltisley and Caxton Gibbet roundabout from 8pm Friday 30 May to 5am Monday 2 June 2025.
Diversion
We will divert traffic north along the B1040 St Ives Road and then east to rejoin the A1198 and travel south to Caxton Gibbet roundabout.
A1 northbound weekend closure - May 2025
We are sheet piling close to the A1 at the northern section Kelpie Marine as we continue to construct the new entrance to the site.
To work safely, the A1 northbound between Tempsford and Black Cat roundabout will be closed from 9pm Friday 30 May until 5am Monday 2 June 2025.
Diversion
We will divert traffic off the A1 at Tempsford and to continue north on St Neots Road through Barford. Traffic will then head west on the A428 via St Neots and rejoin the A1 northbound at Wyboston.
A1198 Ermine Street South closure - May 2025
We are building the new northern roundabout at Caxton Gibbet.
To work safely, the A1198 Ermine Street South will be closed in both directions between Caxton Gibbet roundabout and Papworth Everard from 8pm Thursday 22 to Friday 30 May 2025 (24-hours).
Diversion
We will divert traffic along the A428 towards St Neots. At the new Eltisley North roundabout traffic will continue northbound on B1040 St Ives Road and rejoin the A1198.
A1 northbound overnight closures - May 2025
We are clearing area close to the A1 in preparation for construction of the new Kelpie Marine access route.
To work safely, the A1 northbound between Tempsford and Black Cat roundabout will be closed overnight (9pm - 5am) from Monday 19 until Friday 23 May 2025.
Diversion
We will divert traffic off the A1 at Tempsford and to continue north on St Neots Road through Barford. Traffic will then head west on the A428 via St Neots and rejoin the A1 northbound 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.
Give us your feedback
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
Long term changes
Eltisley junction opens to traffic - from April 2025
As part of the construction of the new A421 dual carriageway between the Black Cat roundabout and Caxton Gibbet,
We're making changes to to how drivers use the A428 at Eltisley:
- we'll remove the B1040 north junction at St Ives Road
- drivers will use two new roundabouts linked by a bridge crossing the new dual carriageway.
From 14 April 2025, we'll direct traffic on the A428 onto the new junction at Eltisley.
Following this we'll:
- remove the closed section of A428 carriageway
- build a new connection linking Cambridge Road (Eltisley) and the new southern roundabout.
We expect to reopen Cambridge Road (Eltisley) in summer 2025.
Changes to Caxton Gibbet - June 2025
As we build the new dual carriageway between the Black Cat roundabout and Caxton Gibbet, we're changing the A428 and A1199.
From June, we'll redirect traffic on the A428 onto a new stretch of road.
On this new section, if you're driving towards Cambridge you'll use the newly built northern roundabout.
Then you'll take the A1198 southbound exit towards the existing Caxton Gibbet roundabout.
From there, you can either continue on the A1198 or rejoin the A428 towards Cambridge.
If you're driving towards St Neots, follow the same route in the opposite direction.
Once we've finished the switch, we'll remove the old section of the A428 before building the new dual carriageway.
Changes to Cambridge Road, St Neots - June 2025
We're changing the A428 at Cambridge Road near St Neots.
From June, we'll redirect traffic on the A428 onto a new stretch of road.
On this new section, if you're heading towards Caxton Gibbet, follow the new route through the northern roundabout.
Then cross the bridge and continue through the southern roundabout to rejoin the A428.
If you're driving towards St Neots, follow the same route in the opposite direction.
Once we've finished the switch, we'll remove the old section of the A428 before building the new dual carriageway.
Black Cat roundabout layout change - summer 2025
As we progress with the junction upgrade at Black Cat roundabout we will make changes to the road layout.
In the summer, we will open new free flow links between the A421 and A1. We will also close the northern section of the roundabout, which will temporarily stop road users travelling south on the A1 from the A421.
Travelling north from the A1 northbound
The Black Cat roundabout will be reduced to one lane for A1 northbound traffic.
To continue north towards St Neots, use the right-hand lane. To access the A421 towards Bedford or Roxton, use the left-hand lane.
Due to the northern section of the roundabout being closed, northbound vehicles can only continue west on the A421 or north on the A1.
See route map for road users travelling north from A1 northbound
Travelling north from A421 eastbound
As you approach the Black Cat roundabout on the A421, you will be diverted onto a new single-lane free-flow link, which will take you directly onto the A1 northbound towards St Neots.
Due to the closure of the northern section of the roundabout, A1 southbound access will not be possible.
Drivers wishing to travel southbound on the A1 have two options:
- Continue north on the A1 to Wyboston, then loop back southbound.
- Exit the A421 at Cardington, take the A603 via Moggerhanger towards Sandy.
See route map for road users travelling north from A421 eastbound
Travelling west from A1 southbound
As you approach the Black Cat roundabout, the A1 southbound will be reduced to three lanes.
Drivers traveling south on the A1 and intending to head west toward Bedford or Roxton should position themselves in the right-hand lane.
Those continuing south towards Sandy should use the two left-hand lanes.
On the roundabout itself, a concrete barrier will separate the lanes for Roxton and the A421 from the A1 southbound. This safety measure ensures that road users stay in their designated lanes while using the junction.
See route map for road users travelling west from A1 southbound
Temporary road layout at A1 / A421 Black Cat roundabout
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
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.
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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