Newport M4 traffic eased 'for almost a third the cost'
Congestion on the M4 around Newport could be eased for around a third of the cost of the Welsh government's motorway proposals, a think tank says.
Ministers are consulting on plans for a £1bn relief road to be financed under new borrowing powers.
The Institute for Welsh Affairs (IWA) says upgrading the A48 and a road through the city's former steelworks is an "affordable" £380m alternative.
The Welsh government has said other options do not offer "a long-term solution".
Maria David reports.
Hear Eye on Wales on BBC Radio Wales on Sunday, 8 December 2013 at 13:30 GMT