Opinion: road building won’t cut congestion or boost the economy

Despite promises of reduced traffic congestion and a boost to economic growth, increased road capacity on the M25 shows that enlarging roads has few tangible benefits, says Honorary Professor David Metz (UCL Centre for Transport Studies). British politicians, national and local, tend to like investing in roads. The Treasury believes that the Department for Transport's approach to economic analysis is sound, and so is willing to award substantial funds. The department is happy to accept them, as are the civil engineering contractors that benefit. The most recent result is a £27.4 billion investment programme designed to maintain and enlarge England's motorways and A-roads over five years. Part of this will involve creating so-called smart motorways, where the hard shoulder is converted into an extra lane for moving traffic and electronic message boards broadcast information to control the speed of drivers and manage incidents. This innovation has raised safety concerns, with some worried about the risk of collisions in the event of a breakdown.