The Does East Anglia need another motorway? Debate (NCE 2 May) touched on some pertinent issues concerning the pros and cons of new motorway capacity, but both contributors appear to have missed some vital points.
Recent history has shown us that new or widened motorways fill up extremely quickly. The reasons include diversion from other roads, economic growth and induced traffic.
There is much debate about so-called soft measures such as company travel plans and teleworking and about how much public transport can accomplish. While these may make some contribution to reducing travel demand, the evidence against is rather more compelling. Similarly, public transport is rarely able to cope efficiently with travel demand.
We therefore need effective demand restraint which will allow road capacity to be increased, but protect against induced traffic.
New and imaginative measures to control growth include ramp metering, high occupancy vehicle lanes, motorway tolling or area wide road user charging.
If there is a need for a new transport connection in East Anglia, major new road capacity may be the best way of achieving this. But it will need control measures, at least to prevent commuters travelling further to work in London.
David Hardcastle, director of transport planning, Halliburton KBR, david. hardcastle@ halliburton. com