Plant hire and haulage bodies warn of M4 44-tonne limit breaches around Newport

The Construction Plant-hire Association (CPA), the Road Haulage Association and the Heavy Transport Association have warned members of an increasing number of reported breaches of the 44-tonne weight restriction on the M4 between junctions 24 and 28 around Newport.

In a member update, the CPA said the reported breaches of the 44-tonne gross train weight (GTW) limit covered both eastbound and westbound movements.

The association said it understood that enforcement activity was being carried out in response to a structurally weak asset on that section of the motorway. The alert does not name the asset or say which body is carrying out the enforcement.

The reminder to operators

The three associations set out three points for operators and transport managers.

First, where a movement has been notified and a route agreed, drivers and operators must follow that route without deviation.

Second, operators should brief drivers on the importance of the notified route and the potential consequences of taking alternative roads or making unauthorised diversions.

Third, where road closures, incidents or other unforeseen circumstances make the notified route unavailable, operators should seek appropriate guidance before proceeding via an alternative route, the CPA said.

The restriction

A Welsh Government temporary order prohibits all vehicles over 44 tonnes, other than those being used for the works, on the M4 between junction 24 (Coldra) and junction 26 (Malpas). The order came into force on 8 April 2026.

The length covered by the order is shorter than the junction 24 to junction 28 section referred to in the associations' alert. Neither document reconciles the difference.

The 2026 order follows two earlier temporary prohibitions. An order imposing the same 44-tonne limit between junctions 24 and 26 came into force on 11 August 2023, according to the Welsh Government.

Before that, a temporary 44-tonne prohibition covering junction 25A (Grove Park) to junction 28 (Tredegar Park) came into force on 29 May 2021.

Abnormal loads and notification

The notification requirement at the heart of the associations' reminder was set out by the Welsh Government in a written Senedd answer on 20 December 2021, responding to question WQ84074 tabled by Natasha Asghar MS (South Wales East) on 10 December 2021.

The Deputy Minister for Climate Change said at the time that the 44T limit was in place on the M4 around Newport between junctions 24 and 28, and that it had been imposed because of the structural condition of the Ebbw river bridge at junction 28. The minister said the Welsh Government intended to remove the restriction once strengthening works were completed in summer 2022.

Any vehicle over 44T is classed as an abnormal load and must notify the trunk road agent, the minister said. Rerouted abnormal loads were required to use the Southern Distributor Road around Newport.

By December 2021, 85 abnormal load movements had been notified to the South Wales Trunk Road Agent since the restriction began and had been told to reroute via the Southern Distributor Road, according to the answer.

The same 2021 answer said the Driver and Vehicle Standards Agency was responsible for stopping HGVs and policing weights on the road network, and that the Welsh Government did not itself hold figures on vehicles stopped. That statement relates to the 2021 restriction and the associations' alert does not identify who is enforcing the limit it refers to.

The CPA said a fuller communication attached to its member update gives further information and detail on the breaches.