When it comes to transport, and transport investment in particular, many wild claims are made about the benefits of new road building, very often based on suspect modelling and dubious economics. Meanwhile, in order to maintain an unwavering support for new roads it is essential to close your mind to the rising evidence and research that shows that new roads generate new traffic and that congestion relief is often short term and does not deliver the economic benefits claimed.
It also creates a raft of economic and social costs and issues in addition to the huge environmental damage it can cause.
These pages help to spell out a few of the facts:
Air Pollution (legal issues)
Economic Impacts
Health Impacts