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
  • Friday 13 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. 

See A428 diversion route map.

UK Power Network are removing overhead power cables close to the A1 northbound carriageway.

To work safely, the A1 northbound between Tempsford and Black Cat roundabout will be closed overnight (9pm - 5am) from Monday 9 to Thursday 12 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.

See A1 northbound diversion route map

We are finalising the new Roxton Road link, including road surfacing, road markings, kerbing, and tie-ins with existing roads.

To work safely, we will have daytime closures at the following times:

  • Roxton Road will be closed between 7am and 5pm on Monday 9 and Tuesday 10 June 2025.
  • Chawston Lane will be closed between 7am and 5pm on Wednesday 11 June 2025.
  • The Lane, Wyboston, will be closed between 7am and 5pm from Monday 16 June to Friday 20 June 2025.

Diversion

For closures of Roxton Road and Chawston Lane, we will divert traffic via The Lane onto the A1 northbound.

For closures of The Lane, we will diver traffic via Roxton Road and onto Bedford Road towards Black Cat roundabout.

We are surfacing and installing new kerbs on The Lane as part of the new Roxton Road link. 

To work safely, The Lane, Wyboston, will be closed from 9pm Friday 16 to 5am Monday 20 June 2025. 

Diversion

We will divert traffic via Roxton Road and onto Bedford Road towards Black Cat roundabout.

We are building the new embankments close to the A421 carriageway.

To work safely, the A421 will be closed in both directions between Renhold Interchange and Black Cat roundabout from 9pm Friday 27 to 5am Monday 30 June 2025. 

Diversion

We will divert traffic via the A603 at Cardington to A1 northbound at Sandy to the Black Cat roundabout.

See A421 diversion route map

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. 

Eltisley junction layout from April 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. 

Caxton Gibbet route map.

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. 

Cambridge Road, St Neots route map.

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

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.

View temporary road layout map

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

View diversion route map

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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