M4 Newport relief road public inquiry date announced
A delayed public inquiry into a new £1.1bn six-lane motorway south of Newport will begin on 28 February.
Economy Secretary Ken Skates has published his revised case for an M4 relief road, following updated traffic projections.
It comes as a formula predicting future traffic, published by the UK government earlier this year, has been changed following Welsh Government complaints.
Mr Skates said it had been based on "zero-growth" in population.
The Welsh Government wants to build the new motorway to relieve congestion on the current M4 north of Newport through the Brynglas tunnels.
The inquiry, which will examine the controversial plan and alternatives, had been due to start on 1 November.
When could the M4 relief road be built?
The existing Welsh Government timetable for the scheme predicts diggers in the ground by spring 2018.
It estimates autumn 2021 as the date when the new stretch of the M4 will be ready for motorists.
By then it would have been about 28 years since the road was first envisaged in 1993.
The current section of the M4 through central Newport will be reclassified as a non-motorway road by autumn 2022.
Objectors to the scheme may, however, attempt to challenge it in the courts via the judicial review process - something that could delay the project further.
The relief road's opponents include environmentalists, opposition politicians and Labour backbench AMs with concerns ranging from cost to the impact on the environment.
The details for the revised case for the relief road came as Mr Skates outlined his plans for transport investment over the next five years to a gathering of business people at Cardiff Airport on Wednesday.
He said the government was publishing a "full technical, economic and environmental report" of the M4 scheme.
The public inquiry would begin on 28 February 2017, with a pre-inquiry meeting held on 27 January, Mr Skates confirmed.
The Welsh Government is using a formula from the Department for Transport (DfT) to predict future traffic growth as part of its case to justify building the preferred so-called "black route" for the M4 relief road.
But a new version of this formula caused a delay to the public inquiry proceeding.
Sources said the new formula from the UK Department for Transport had predicted slower growth in traffic than previously expected.
BBC Wales was told ministers needed to postpone the inquiry to ensure the case for the preferred route was based on the most up-to-date evidence, or risk being vulnerable to legal challenge.
Following the Welsh Government's complaints about traffic forecasts earlier this year, the Department for Transport has published an updated set of traffic forecasts taking into account more "up to date and robust" evidence about housing growth.
The data includes assumptions on the number of future homes in south Wales based on a local development plans for future growth in south Wales and mid-Wales.
'Wasn't accurate enough'
Mr Skates told BBC Wales: "We are looking at a major increase in the number of people will wish to travel, whether it be by rail, whether it be by bike, whether it be by car.
"In terms of road usage, there will be an increase that justifies the black route of the M4," he said.
He said some of the data from the new model was "incorrect quite frankly".
"It was based on assumptions of zero-growth in terms of population," he said.
"That is not right because all of the traffic modelling shows that there will be an increase in road use, and all of the modelling shows that there will be an increase in population within the region."
He said new modelling was brought forward after the Welsh Government had made "representations" that the data was wrong.
Other projects in the five-year plan include improvements to the A40, A55 and A494, the south Wales and north Wales metro schemes, a new rail franchise, a ports development fund, the development of a third Menai crossing, and better bus services.
Mr Skates revealed that a consultation on congestion solutions for the A494 and A55 in north east Wales - which could cost more than £200m - would take place in March 2017.
Russell George, economy spokesman for the Welsh Conservatives, said: "It has long been clear that a motorway grade solution is necessary to relieve congestion south of Newport, and business leaders and motorists are looking to the Welsh Government for a clear sign that this project is on track."