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 updates

Update - A1198 Ermine Street South Friday 3 May overnight closure cancelled

There will be no closure of the A1198 overnight on Friday 3 May.

We completed works on the A1198 on Thursday 2 May.

A428 overnight closures

Before we can begin working on the new junction and slip roads at Cambridge Road in mid-May, we need to install a 40mph speed restriction, roadworks signs, safety barriers, narrow lanes, speed cameras and CCTV on the A428.

For safety reasons the works will be carried out under overnight closures at the following locations:

Wyboston roundabout to Cambridge Road roundabout - Thursday 9 – Friday 10 May, 8pm – 5am.
Cambridge Road roundabout to Caxton Gibbet roundabout - Monday 13 – Wednesday 15 May, 8pm – 5am.

Once complete, the narrow lanes will be in place until spring 2025 and will allow additional space at the side of the road to provide a safer working environment for our workforce to upgrade the junction at Cambridge Road.

Diversion route

Westbound traffic will use the A1198 north then A14 west, at Brampton Hut A1 south then at Wyboston west on A428. Eastbound traffic will use the same route in reverse.

Weekday closure - The Lane, Wyboston

We will be closing The Lane from Monday 20 to Friday 24 May between 9am and 3pm.

The closure is to allow us to carry out vegetation clearance and the installation of a site access on The Lane, in Wyboston

As part of the A428 Black Cat to Caxton Gibbet improvements, access to the A1 from The Lane, Nagheads Lane, Chawston Lane and several private dwellings will be closed for safety reasons.

We will be providing an alternative link road to give these lanes and private dwellings access to the Black Cat junction. This link road will run between The Lane at Wyboston and Roxton Road, also picking up traffic from Nagshead Lane and Chawston Lane. A new bridge will then take traffic over the A421 to meet Bedford Road, where traffic can join the roundabout at the Black Cat junction. The new link road will increase safety and reduce rat running through the lanes to get to the A1.

Diversion route

From A1 northbound traffic will be diverted along the A1 to Chawston Lane and Roxton Road. No access to the A1 from The Lane.

Access to residents’ properties along The Lane will be maintained.

New layout on Black Cat roundabout

There has been a switch of the layout on the Black Cat roundabout, and the A421 Westbound (Towards Bedford/MK). These changes are essential to facilitate the construction of the scheme without closing any part of the road permanently, therefore trying to reduce ongoing disruption.

We have since added lane lines for traffic to follow. The inside lane for All Routes, predominately for A421 West and Roxton. The outside lane for A1N Only, continues around the roundabout. If you find yourself in the wrong lane, please continue around the roundabout, rather than move in front of vehicles heading toward the A421 West (Bedford/MK).

Black Cat roundabout diagram of new layout

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.

The junction is extremely complex to manage due to the many points of entry and exit and the multiple lanes available, this is exacerbated as we are making a change to a layout which customers have become used to over several years. We need to allow a period for customers to become familiar with the new layout and for them to adjust to the new arrangement.

However, we are constantly working on other possible measures or layout adjustments which may need to be implemented if the familiarity does not come. We do not want to make any situation potentially worse for our customers, whilst relying on driver behaviour to support the latest layout.

What you will see

40mph speed restriction - will start approximately 1.2 miles on the approach to the Black Cat roundabout
Speed cameras will be in operation to enforce the 40mph speed restriction
Narrow lanes on A421 on approach to A1 Black Cat
Temporary road realignment markings
Workspace safety barriers and roadwork signs
Vegetation clearance

Vegetation clearance

We will be carrying out vegetation clearance along our roadside verges ready for the start of the construction works later this year. This activity at times may be noisy, and we’d like to apologise in advance for any disturbance caused.

Please remember:

To plan your journey accordingly.
Traffic approaching the closure location shortly it begins is likely to be subject to the diversion while the closure is put in place.
We always try to stick to timings, however these closures may be amended due to poor weather or operational reasons.
You can get real-time traffic information via www.trafficengland.com.

How do we plan diversions, road closures and speed limits?

We have monitored traffic volumes at 24 different locations in advance of construction and will continue to monitor it throughout the construction period. Click on some of the headings below to find out how we'll keep traffic moving during construction.

We've carried out a ‘highest safe speed' assessment to work out the highest, safest speed you can travel through the roadworks.
Our assessment found that a 40mph temporary speed limit is necessary to protect the road user and workforce for works to be carried out safely.
The temporary speed limit means junctions can operate under normal capacity, resulting in a lower number of full road closures.
The speed limit of 40mph means the temporary barriers and narrow lane systems are safer for all road users.

We have planned construction so there are minimum road closures, diversions and road layout changes to reduce confusion.
Road closures will be minimised as much as possible to only essential works, such as demolition works or major phasing changes.
We will use static narrowed lanes and temporary alignments to maximise the construction work areas and keep the number of full closures as low as possible. For example, we will keep two lanes open on the A421 eastbound when we move into construction.
At later stages in the construction we will use some of the newly constructed slip roads to keep the traffic moving: we will use slip roads and link roads to create a temporary ‘large gyratory’ at the Black Cat while the new A1 underpass is constructed.
The A1 will be kept open as much as possible, although it is expected that A1 closures will be needed to allow the safe construction of parts of the new road. These may require a combination of weekday night closures, weekend night closures and full weekend closures.

We have a commitment to you the road user to provide a safe and suitable diversion route around a closure.
We will only use diversion routes that can take the type and volume of traffic that is being diverted.
The diversion routes will stick to major A roads on our road network to minimise rat running through local villages and on local roads.
We have to follow the diversions which are set out in the development consent order (which is like our planning permission).
We aim to reduce disruption in your lives by managing the traffic with clear signage and advance warning.
By standardising the way we do this, we can provide safer and more reliable journeys for you, resulting in familiarity along unfamiliar routes.
All diversion routes are agreed with the relevant local authorities.

Managing traffic flow during construction

Our visualisation shows how we’ll keep the traffic moving while we build the new Black Cat junction.

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