The A414 between the M1 at Hemel and St Albans can shut 8pm Friday to 6am Monday from 11 September. National Highways expects the works to run to August 2027.
The A414 between the M1 at Hemel Hempstead and Park Street Roundabout in St Albans can be closed for whole weekends from Friday 11 September.
A National Highways order allows the road to shut from 8pm on a Friday until 6am on the Monday, in both directions, as well as overnight from 8pm to 6am on weeknights. It also imposes a 40mph speed limit that applies 24 hours a day on the approaches to Park Street Roundabout.
The order stays in force until the works are finished. National Highways says they are “expected to last until August 2027” (Public Notice Portal, 27 August 2026).
That is close to a year of weekends on the most direct road between Hemel Hempstead and St Albans.
What the order actually does
The A414 here is a trunk road, so National Highways is the authority, not Hertfordshire County Council. The notice was advertised on 27 August 2026 in The Herts Advertiser, the St Albans paper. It was not carried in the Hemel batch of notices published the day before.
The order allows four things:
- a 40mph speed limit, 24 hours a day, eastbound from 1,400 metres west of Park Street Roundabout to the roundabout, and westbound from the roundabout for 500 metres
- overnight closures, 8pm to 6am, of the A414 in both directions between the M1 junction 8 slip roads and Park Street Roundabout
- full weekend closures, 8pm Friday to 6am Monday, of the same stretch
- a 2.4 metre vehicle width restriction at times in the offside lane, eastbound from 700 metres west of the roundabout and westbound for 500 metres from it
The eastbound closure runs from where the A414 splits from the M1 junction 8 southbound entry slip road. The westbound closure runs from Park Street Roundabout to where the A414 merges with the M1 junction 8 northbound exit slip.
The speed limit does not apply to emergency service or special forces vehicles. The closures do not apply to emergency service, traffic officer, works or winter maintenance vehicles.
The order comes into force on 11 September 2026 and can stay in force for up to 18 months. It revokes an earlier order covering the same stretch, made this year and numbered 0145.
The diversions, and why one of them matters to Hemel
The notice publishes signed diversion routes for both directions. The westbound route has two options, and one of them brings St Albans traffic through Hemel Hempstead.
Eastbound, traffic leaves the M1 at junction 8 and follows the A414 Breakspear Way, the A4147 Leverstock Green Way, Hemel Hempstead Road, Bluehouse Hill, the A5183 Verulam Road, High Street and the A1081 London Road to London Colney Roundabout.
Westbound, drivers can either reverse that route through St Albans, or take the longer way round via Watford. The Watford option runs along the A405 North Orbital Road, joins the A41 North Western Avenue at Leavesden Green, continues on the A41 Watford Road, then comes into Hemel Hempstead on the A414 Two Waters Way, St Albans Road and Breakspear Way.
What the works are for
The notice says the order is needed “to enable infrastructure works to Park Street Roundabout and a section of the A414 to be carried out in safety”. It does not say what the works consist of, or who is paying for them.
National Highways’ own closure report is more specific. It describes the current A414 closures at Park Street as “S278/bypass works on behalf of Galldris Group” (National Highways closure report).
An S278 is an agreement under section 278 of the Highways Act 1980, headed “Agreements as to execution of works”. It lets a highway authority carry out works on the public road where another party “pays the whole or such part of the cost of the works as may be specified” (legislation.gov.uk). In practice that means highway works paid for by a developer rather than out of the roads budget.
General enquiries on the order go to Galldris Services, a civil engineering contractor based in Enfield, rather than to National Highways.
National Highways has not published a scheme page for these works. It does have one for a separate and much smaller job on the same stretch: a £1.4 million lighting and road marking upgrade at Park Street Roundabout and the M1 slip roads, replacing sodium lights with LEDs, which it dates July to October 2026. That page describes overnight working between 8pm and 6am, and its only listed full closures were in July (National Highways).
So the smaller scheme has a page and the bigger one does not. For now the statutory notice and the weekly closure report are the only public record of what is about to happen to the A414.
It has already started
The order does not begin until 11 September, but the eastbound carriageway is already closing under the arrangements it replaces.
National Highways’ closure report for the week beginning 2 September lists the A414 eastbound, from Breakspear junction to Park Street Roundabout, closed from:
- 8pm on Thursday 3 September to 6am on Friday 4 September
- 8pm on Friday 4 September to 6am on Saturday 5 September
Those are overnight closures. The weekend power is what changes on 11 September.
What it means for you
The restrictions apply only when the signs are physically out, so not every weekend between now and August 2027 will be affected. Nobody has published a schedule of which ones will be.
That leaves one practical answer: check the closure report before you travel, rather than assuming. It is updated weekly and covers the coming seven nights.
Three things worth knowing if you live in Hemel Hempstead:
- The direct route to St Albans, the hospital, the station and the city centre may be gone at weekends. Both alternatives are substantially longer.
- If the Watford diversion is signed, extra traffic will come through Two Waters and along Breakspear Way. That is a route many people in Apsley, Nash Mills and Leverstock Green use for local trips.
- The 40mph limit near Park Street Roundabout applies all day, every day, from 11 September, whether or not any closure is in place.
The works land in the same fortnight as several other closures around the borough, including the M1 northbound between junctions 6 and 8 and a seven-day gas main closure on Lower Yott Road, off the A414 St Albans Road, proposed from 14 September. Our Hemel Hempstead roadworks and travel page tracks all of them and is updated against the primary sources.
Sources
- National Highways notice, published 27 August 2026: The A414 Trunk Road (M1 Junction 8, Hemel Hempstead to Park Street Roundabout, St Albans, Hertfordshire) (Temporary Restriction and Prohibition of Traffic) Order. Source for the 40mph limit, the overnight and full-weekend closure powers, the width restriction, the diversion routes, the vehicle exemptions, the 11 September start, the August 2027 expected end and the revocation of order 0145.
- National Highways road closure report, week beginning 2 September 2026, for the A414 eastbound closures on 3 and 4 September and the description of the works as “S278/bypass works on behalf of Galldris Group”.
- Highways Act 1980, section 278 for what a section 278 agreement is and who pays.
- National Highways, A414 Park Street Roundabout to M1 lighting and road marking improvements for the separate £1.4 million lighting scheme, its July to October 2026 dates and its working hours.
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