The Government's cherished national road building programme was put in jeopardy yesterday by the publication of a report from an advisory body suggesting that the financial basis for many new road schemes is fundamentally flawed. Ministers responded to the report, from the Standing Advisory Committee on Trunk Road Assessment, by agreeing to reassess all future road schemes using new criteria to gauge their impact on generating traffic.
The committee's key finding is that the construction of new roads induces extra traffic, upsetting previous Department of Transport conventional wisdom which said there was no such effect. This means that many of the benefits of road schemes, which are assessed largely in terms of time saved by motorists, will be lost as congestion builds up again to its previous levels.
The SACTRA report by independent advisors to the Department of Transport was completed in May but ministers have delayed publication while considering their response.
The Government spends £2bn a year on the national road building programme but this was cut by £200m a year in the Budget. In a briefing yesterday, John Watts, the Minister for Railways and Roads, said that schemes which had already gone through the public inquiry process would not be reassessed.
But environmentalists said they would challenge this decision. Tony Burton, senior planner of the Campaign for the Protection of Rural England, said: "This opens up an interesting legal testing ground. I'm sure there will be challenges."
Mr Watts also promised further research to develop new assessment criteria for road schemes. The report says that the present methods lack "caution and robustness".
The new criteria appeared to have claimed their first casualty as Brian Mawhinney, the Transport Secretary, announced that the controversial plan for the A34 Newbury by-pass, considered by environmentalists as the most damaging road scheme in the country, would be put on hold while alternative routes would be considered.
However, Mr Watts denied that there was any connection between the cuts in the road programme and the publication of the SACTRA report.