Watford road users are being advised to expect significant delays when repair works start on the Napsbury Lane bridge in St Albans.

The works are being carried out on behalf of Hertfordshire County Council in late July, on the bridge which crosses the A414 between Park Street roundabout and London Colney roundabout.

This is to address corrosion, which impacts the integrity of the bridge’s structure.

Preparation work will start on Saturday, July 25 with a full night-time closure of both east and westbound carriageways (8pm top 5am) - later full night-time closures are detailed below.

Starting from Sunday, July 26, there will also be a 24 hour lane closure for 16 weeks on the A414 North Orbital in both eastbound and westbound directions, and there will be road closures on Napsbury Lane (B5378) for part of this period.

Terry Douris, cabinet member for highways, said: “While there is never a good time to do works of this nature, the bridge will soon be coming to a point where its safety might be compromised and we have a duty to make sure that all road users are safe.

“We’ve arranged for the start of this £500,000 scheme as much as possible. But with essential works of this nature, it’s unfortunately inevitable that road users will experience some delays.

“We appreciate that these road works are likely to cause disruption and inconvenience to motorists and we thank everyone for their co-operation and patience while the work is in progress.

This scheme forms part of Hertfordshire County Council’s ongoing commitment to maintain and improve our roads.”

Where possible, road users are advised to avoid this section of the A414, plan ahead and allow extra time for their journeys.

Additionally, road users are advised that starting ahead of the lane closures on the A414, from July 13 to 15 July there will be full night closures (10pm to 5am) on Napsbury Lane (B5378) on the bridge over the A414, followed by a single lane closure, northbound, between July 27 to 29 July, a full night closure of the bridge on July 30 and a single lane closure, southbound, between August 3 to August 5. This is due to essential re-surfacing and bridge joint replacement works.

Full details, including the road closure and diversion information, are available on http://hertfordshire.roadworks.org/.

The work is weather dependent and from time to time unforeseen circumstances can arise and work may continue outside the advertised hours. Any changes to the proposed start date, duration or hours will be announced on the information boards on site and will be available at http://hertfordshire.roadworks.org/.

Bus service routes may be affected by these works – for details of any changes you can visit www.intalink.org.uk and look in the ‘service disruptions’ section.

A414 full night-time closures:

Thursday, July 23 – westbound carriageway

Friday, July 24 – eastbound carriageway

Wednesday, September 23 – westbound carriageway

Thursday, September 24 – westbound carriageway

Friday, September 25 – westbound carriageway

Monday, September 28 – westbound carriageway

Tuesday, September 29 – westbound carriageway

Wednesday, September 30 – westbound carriageway

Thursday, October 1 – eastbound carriageway

Friday, October 2 – eastbound carriageway

Monday, October 5 – eastbound carriageway

Tuesday, October 6 – eastbound carriageway

Wednesday, October 7 – eastbound carriageway

Thursday, October 8 - eastbound carriageway

Tuesday, October 27 – westbound carriageway

Wednesday, October 28 – eastbound carriageway