DEFLATING THE THEORY THAT ROADS GENERATE TRAFFIC

The author claims that the opening of a new urban road, particularly an orbital project like the m25 motorway, does not necessarily lead to increased traffic caused by commuters changing from public transport to private car. It is likely that integrating and subsidising fares would have a more significant effect in reducing congestion than the building of highways in central London where most of the costs must be measured by the reduction in speed creating longer journey times and increased fuel consumption. A lower patronage of public transport results in a reduced service. There are also environmental costs if the new road does not reduce congestion. Research shows that orbital schemes increase traffic on radial routes in the outer area but not necessarily into the central area. Most commuter routes are radial and so more direct improvement of radial road corridors can be expected to have the largest effect on public transport. Environmental factors should play a much greater role in the design of new urban roads than in the past as, although costs may be increased, an environmental improvement often increases the prosperity of an area. See also IRRD 285681. (TRRL)