Leading article: The polluter must pay

The Eddington review of transport policy, published last week, only inches us forward in a slow-moving traffic jam, and leaves us thinking that we might have made a bit more progress in a different lane. In simple political terms, the report makes one important point, which is that road pricing is essential. It is, indeed, the optimum means for controlling both carbon emissions and congestion in land transport. A national pricing regime could take into account the emissions of individual vehicles as well as the demand for road space by location and time of day.

Sir Rod Eddington is a former chief executive of BA, not a politician, and so missed the chance to make the policy more electorally palatable. Road pricing will only be accepted by the voter-as-motorist if they are offered a tangible benefit for the money. Otherwise the familiar cry of "revenue-raising scam" will go up. Freer-flowing traffic, investment in public transport and saving the planet are tangible enough, but people need persuading.

Sir Rod also falls victim to the common fallacy of thinking that a bit more capacity in the particular transport bottleneck in which he has a personal interest will boost GDP, make us happier, and deliver us to the sunlit uplands. His report argues for airport expansion on the grounds that a quarter of British flights are delayed by more than 15 minutes. Just as on the roads, however, more capacity will simply generate more traffic.

Sir Rod sounds like the commuting Ford Focus driver who thinks that a right filter on the Bogchester bypass would get him to work 20 minutes earlier. But at least he argues for air travellers to pay the full environmental cost of their journey. And he does not think more investment in railways is the answer to everything. It would be pleasant to have a fast, frequent, reliable and safe rail system covering the entire country, but it would also cost a fortune. The new economics of global warming has begun to tilt the price advantage back towards rail rather than road, but there is a long way to go.

Most of the effort of the Government's policy for the foreseeable future must be devoted to managing - and reducing the carbon impact of - road traffic. Road pricing is the only route to a sustainable future.