24 Jul 2026
The A5183 Watling Street northbound exit from the Park Street roundabout will be closed full‑time, day and night, for approximately four to five weeks over the summer holidays.
This closure will begin tomorrow (Saturday July 25) as part of the redesign of the road layout as part of the Radlett Aerodrome strategic rail freight depot.
Developers SEGRO and Herts Highways have aligned the closure with the main school holidays to expedite the works, reduce the number of night‑time operations, and minimise overall disruption.
Diversion routes will be in place, supported by appropriate signage across the network.
In advance of this, there will be night‑time closures on July 24-26 on the north side of the Park Street Roundabout from 8pm-6am (see diagram below). These closures are required to complete drainage works across the carriageways and to install the traffic management associated with the A5183 Watling Street north exit closure.
Roads affected include the A414 eastbound from the M1 to the A414 slip road to Napsbury Lane, A5183 Watling Street north access and egress to the Park Street Roundabout.
