The public inquiry into Luas seems little related to the traffic reality evolving. The Dublin Transport Initiative, of which Luas is a part, was developed for a Dublin of another era. What none of us realised, when the DTI report came out, was the impact the Celtic Tiger would have on the most critical factor in traffic congestion, the level of car ownership.

Most of the DTI strategy would still do more good than harm, if implemented as a stop-gap. But we will never properly solve the congestion we face now with the DTI proposals alone. We need to think radically.

Let us fast-forward to the crux of the problem. Congestion happens, obviously, when there's more traffic than the roads can take. Our situation now is that traffic growth has swamped the network.

Since we have little scope to build more roads, we must search for more efficient ways to use the existing network. It's common ground with everyone that switching people to public transport is the main way to squeeze more capacity from the road network. Making that happen is the key, and where I believe we have gone totally wrong.

What determines the number of vehicles in the city is how many private cars people own.

As the number of cars has exploded, so has the traffic, and thus public transport becomes less attractive.

I suggest that:

Nothing on the drawing-board so far, including Luas, is likely to cause a major shift to public transport.

Our present persuasive strategy, of forcing people towards public transport by making their life as motorists hell, is doomed to failure.

The psychology at work here is very simple: if traffic is going to be hell anyway, people would rather endure it in their own car than on public transport. When people own cars, they will choose to use them, even if it's unpleasant. We've ignored that psychology in our traffic planning.

While our goal of moving people to public transport is right, the ways we're using to reach that goal will never work. The tough medicine to solve this problem has two parts:

1. Public transport that offers a radically better way of getting from A to B, to a motoring public who love their cars.

2. Making it significantly more expensive for motorists to use those cars, by rationing the use of city streets on a pay-as-you-go basis.

The two parts interact and are inseparable. Public transport will never be attractive unless it's fast and reliable. So we need a mechanism to cut traffic to a point where public transport has the space to become an attractive alternative.

I believe the only mechanism that will work is rationing road use through price. Technology now exists to charge people for using particular streets at particular times. This presents a series of costed alternatives: going at peak times will cost more, going through the busiest streets will cost more than going by alternative routes.

Instead of people deciding to use their car simply because they own it, road pricing adds another dimension to shape their behaviour. All our experience suggests that behaviour is affected powerfully by price, whereas inconvenience has often only a marginal effect.

Road pricing is already a practical reality, notably in Singapore, and it works. But until now for us it has been politically taboo. I believe the political taboo against road pricing is a hoary old myth, just waiting to be punctured. I feel people would accept a carefully-thought-out strategy of road pricing if they saw it offering a way out of permanent gridlock.

But road pricing on its own is no solution unless a proper alternative to private transport is provided. If you bring in road pricing, there must be fast, reliable public transport to switch to, otherwise the price incentive does no more than increase the motorist's pain.

The beauty of this approach, however, is that the two aspects complement each other. Effective road-pricing frees up space for public transport to work efficiently. At the same time it can provide money to invest in quality public transport.

Charging motorists for the use of city roads would be a quantum leap, but perhaps the time has now come to consider it. We should be talking road pricing, not Band-Aid solutions like light rail and quality bus corridors.

Feargal Quinn is an Independent member of Seanad Eireann and chief executive of Superquinn