The need to cope with the growing congestion crisis has been the motivating force behind the national transport debate, writes Christian Wolmar.

The amount of traffic was forecast to go up by between 83 per cent and 142 per cent between 1988 and 2025. The pro-roadbuilding group, the British Roads Federation, calculates that in the past 10 years, traffic has increased by an average of one-third on all roads, with 61 per cent growth on motorways.

In the introduction to the Green Paper, Sir George Young put the problem in a nutshell: "Traffic growth highlights the question of whether the aims of widening choice, of improving the competitiveness of our economy and protecting the environment ... can be reconciled."

But the paper has failed to come up with a strong programme for national government to reduce congestion. Instead, it relies on local authorities to tackle the problem.