Business community all black and blue
A clear divide has emerged on what kind of road should be built to ease congestion on the M4 around Newport.
There are two sides: the so-called black route (or a variation of it) which will be a £1bn motorway running across the Gwent levels to the south of Newport and the so-called blue route, which is in effect an upgrade of the southern distributor road which runs just to the south of Newport.
This latter option would be considerably cheaper and quicker to build.
The Welsh government is in the process of consulting. It favours the black route, running between junction 23 at Magor and junction 29 at Castleton.
At a political level, the Welsh Conservatives support black, while Plaid and the Lib Dems support blue.
The leader of the Welsh Conservatives, Andrew RT Davies, has accused Plaid of trying to score political points rather than thinking of the good of the Welsh economy. Plaid have urged the Welsh government not to dig its heels in on the issue and re-consider its favoured option.
There's also an interesting split that's emerged among the business community with the CBI, which represents big business, favouring black and the Federation of Small Businesses favouring blue.
So far I think it's fair to say much of the debate has focused on raising the cash for the road, rather than the route itself.
If it goes ahead, much of the money will be raised with the Welsh government's new borrowing powers so inevitably many discussions about the project have focused on further financial powers.
A letter to the Economy Minister Edwina Hart from the assembly's environment committee raising concerns about the consultation and a Plaid debate on the M4 this week will, at the very least, generate debate on a major investment.
At a weekly briefing, Plaid's spokesman on the economy Rhun ap Iorwerth set out the case for the blue route, including the speed with which it could be completed compared with a new three-lane motorway.
He said: "The other benefit of the blue route is that it protects the sensitive environmental sites on the Gwent Levels.
"It is hard to put a financial cost on saving the Gwent Levels, but the blue route also saves around £620m, which Plaid Cymru would want to see reinvested in projects elsewhere in Wales.
"We are giving the Labour government a chance to back out of its plans to borrow and spend £1bn on a 14km stretch of motorway; a totally disproportionate way of dealing with congestion.
"Plaid Cymru's alternative plan would be completed more quickly and would leave more money for the infrastructure needs of the valleys, west and north Wales."
'Lessons of history'
The counter view is probably best expressed by the CBI. This is what the chair in Wales, Chris Sutton, told the business organisation's summer lunch last week:
"In our view, the central point is that the blue route does not learn from the lessons of history.
"North of Newport, the existing M4 forms a local by-pass with five junctions - and this is half the problem, it remains a local route trying to cope with motorway traffic.
"So, let's not repeat our error with a 13 junction relief road which once again would mix local and motorway traffic.
"The blue route has been seized upon by the environmental lobby - however it would, by its very nature, cut Newport in half and a fast motorway running through the centre of the city would undoubtedly have a negative impact upon the people of Newport.
"The needs of the environment must continue to be balanced with the needs of the economy."
It's unclear when the Welsh government's consultation will come to an end but once it is done we're expecting a final decision. Inevitably there will be a legal challenge and probably a public inquiry.
Raise a glass
It's a complex issue. One major factor is projected traffic flows. The Welsh government's consultation paper says there's a need for 20% more traffic capacity by 2035.
Stuart Cole from the University of South Wales, who has advised the Welsh government on transport issues, points out that electrification of the Great Western mainline will alone reduce M4 peak traffic flows by 15%.
This isn't going to be a quick process.
In fact Chris Sutton at the CBI came across a public consultation for the proposed route from July 1993, so we should soon be able to raise a glass to celebrate its 21st birthday.