A421 upgrade

A421 upgrade: timings and progress

A421 progress


The initial preparatory roadworks run from September 2018 until February 2019. In March 2019, the major work to lay the dual carriageway will start. The improved A421 road is likely to be ready by the end of 2020.

Speed limits

We are trying to minimise disruption to road users as far as possible during this project. However, our contractors advise that a 40mph speed limit is needed to protect the safety of their workers from the road traffic. We ask businesses and residents to factor that into their journey times and use a suitable alternative route if they can.

There are weight limits zones in surrounding villages, which will be enforced by the police, so lorries should still keep to the main roads for their routes.

At key stages in the construction, we may need to close the road for extra safety. Read information about our next closures and diversion routes.


Fly-through video

This video gives a bird's eye view of the work that we're doing to upgrade this stretch of the A421 road into Milton Keynes. We'll be issuing updated films as we progress the construction.


Back to the top