Traffic on the M4 Severn Crossings has risen sharply, ahead of the promised abolition of tolls at the end of this year.
The twin bridges were operated and maintained by a private concessionaire until 8 January, when they passed to the UK Government.
There was an immediate reduction in toll charges – which are collected westbound only – because VAT was no longer charged. Figures released by Highways England reveal that 1,419,530 vehicles used the crossings westbound in June, compared with 1,289,588 – an increase of 10.1%. In May the increase was 10.7%.
Professor Stuart Cole, emeritus professor of transport at the University of South Wales, said the increase was double the usual elasticity.
'If you put the price down by 10%, demand would increase by 3%,' he said, explaining the usual scenario.
Severn toll prices had reduced by 16% in January. 'Here I would have expected demand to increase by 4% to 5%, but it’s double that. The extra 5% is probably the result other factors [apart from the price reduction].'
One probable factor is a flurry of house-buying in South Wales by people who work in the Bristol and Bath area, stimulated by the Government’s announcement in July 2017 of Severn toll abolition.
Houses are significantly cheaper on the Welsh side of the Severn. Prof Cole said some commuters may already have moved house, to beat expected increases in property prices.
Another factor was disruption to train services through the Severn Tunnel this summer, particularly during engineering blockades for electrification. For example, some passengers travelling to London from South Wales might opt to drive to Bristol Parkway station to avoid using rail replacement coaches from Newport, he suggested.
If the usual demand elasticity applies after toll abolition, traffic on the Severn Crossings is likely to increase by about 30%, said Prof Cole.
'The concern is the capacity of the M4 to deal with this extra traffic,' he added, suggesting roads on the English side of the crossings were already congested in the morning peak.
The Welsh Government is awaiting the results of a public inquiry into the proposed £1.4bn M4 Relief Road, designed to avoid a notorious bottleneck at Newport.
If the controversial project goes ahead, the anticipated opening date is 2024, five years after abolition of tolls is expected to result in a major increase in traffic on the M4 west of the Severn.