The Economist carries an interesting article about road pricing this week, based on the RAC foundation's latest forecast of traffic growth. By 2041, their report says, demand for road space will have increased by 37 percent due to economic and population growth. Given the steady decline in road-building over the last twenty years, and the UK's already clogged-up infrastructure, the future sounds like it is going to be very congested indeed.

This need not be the case. Standstill Britain could easily be averted by a sensible transport policy, which would make addressing both the supply of and the demand for roads a priority. Increasing the supply of roads is simple - it means building more of them. And the best method of regulating demand and allocating road capacity is well established too - road pricing.

The trouble is, both of these policies have encountered noisy opposition. The environmentalists get worked up about new roads (never mind the fact that less congestion equals lower emissions) preferring to force us onto inadequate and crowded public transport. Motorists do not seem to like the idea of paying for road space either - a petition against road-pricing on the Downing Street website attracted 1.8 million signatures.

The explanation may lie in the woefully unimpressive way the government made the case for road-pricing. They failed to point out that pricing would replace other road taxes, rather than add to them, or that many people (rural or off-peak drivers) would actually end up paying less under the new system. Then again, perhaps no one would have believed them anyway, given the current Prime Minister’s affinity to stealth taxes.

The RAC's report recommends a very sensible (and potentially popular) scheme. Fuel duty would be scrapped, and replaced with a 14 pence/l 'carbon charge'. Then motorists would pay per kilometre according to how busy the road was. I would add something to this: the money collected should fund improvement and expansion of the road network. If you are going to make motorists pay, it's only fair to give them something in return.