THE success of Newport's new average speed zone in cutting motorway congestion will depend on how well the speed limit is enforced, experts say.

A Senedd committee heard this week progress was being made on the M4's new 50mph average speed zone around Newport – part of the Welsh Government's strategy to improve traffic flow on a stretch of road regularly beset by gridlock and traffic delays.

"People will realise quite quickly if that is not being enforced," said Peter McDonald of the South East Wales Transport Commission's secretariat. "If we want [the speed limit] to have its desired effect, it needs to be enforced." 

Mr McDonald was joined by transport commission chairman Lord Burns for this week's meeting with the Senedd's economy, infrastructure and skills committee.

Senedd members quizzed the pair on the findings of the commission, set up a year ago to find alternative ways of improving transport around Newport after the M4 relief road project was scrapped.

The commission's early work involved a trio of quick fixes to immediately improve motorway congestion between Junctions 23 and 28.

They said extra patrols by traffic officers and a revision of the filter lanes either side of the Brynglas tunnels should supplement the commission's main initial recommendation – namely, to scrap the system of variable speed cameras dotted along that stretch of the M4.

With evidence suggesting traffic flow was being disrupted by some drivers accelerating and braking aggressively between each variable speed camera, the commission instead backed a fixed 50mph average speed zone that would force motorists to drive at more consistent speeds.

Work to set up the new system is ongoing and should be completed in the spring.

Those quick fixes were followed this year by the bulk of the commission's work on devising a so-called 'network of alternatives' to end the region's reliance on the M4 as the main transport artery.

A final set of recommendations comprised sweeping changes to the city's public transport system, with an overhaul of the South Wales Main Line paving the way for an integrated rail and bus network that would connect workers with jobs in Newport, Cardiff and Bristol.

In the Senedd meeting, Lord Burns said reduced activity on all forms of transport – caused by the coronavirus pandemic – would have little effect on the region's long-term travel needs.

He said he supported the notion of making it easier for people to work from home, but generally people wanted jobs available in cities.

"We don't really see over the long-term that that tendency is going to change," he said. "Many of the jobs that are being created, and jobs that people want to do, tend to be based in those areas."

Lord Burns said it was "very striking" how quickly M4 traffic levels returned last summer after a lull in commuter journeys during the first lockdown.

Looking beyond the pandemic, Mr McDonald said wider population growth meant it was "only a matter of time" before the M4 in Newport reached a point that it could not cope.

"Even if the Welsh Government were to fully achieve its remote-working target immediately... we would still have a very high demand for the [M4]," he said in support of the commission's public transport plans.

The commission's final report has been presented to ministers, and a delivery unit has since been set up to consider how the recommendations can be realised.