Traffic is one of the inevitable consequences of earlier plans to create a motorised city; now that we've got it, we're beginning to realise it doesn't work. Day after day, horror stories multiply about the side-effects of this process of self-strangulation. Traffic chaos has become part-and-parcel of Dublin life - and it's getting perceptibly worse. And though every city suffers from traffic to some degree, the problem here is aggravated by suburbs extending, in reality, from Dundalk to Baltinglass: Dublin occupies a land area twice the size of European cities of comparable population, notably Copenhagen.

Nearly everybody can now see that the city is facing heart seizure, with its arteries clogged by cars and the Liffey quays, in particular, choked by a fleet of trucks heading to and from the port. Just ask the bleary-eyed commuters who must leave their homes 15 or 20 minutes earlier in the morning than they did last year to be sure of getting to work on time.

Or consider the shocking estimate that Dublin's economy is losing at least £1 billion every year because of the time being wasted sitting in traffic jams.

Congestion is no longer confined to the city centre and the main roads leading into it. The suburbs, too, are becoming saturated with cars. According to the Dublin Transportation Office, 137,000 cars hit the road every morning throughout the city and its hinterland. That's 45,700 more trips a day than anticipated in 1994 by transport planners: they did not bargain for a booming economy and, with it, an unprecedented surge in car sales.

Planning always comes back to transport, like a stylus stuck in a groove. If the core of the 1999 Planning Bill was to promote sustainable development instead of just paying lip-service to the concept, the Greater Dublin Area would have to be shaped around a real, functioning and accessible public transport "system".

To help achieve this objective, the 1999 City Plan explicitly seeks to re-balance transportation in Dublin in favour of public transport by facilitating the development of LUAS and the various quality bus corridors, giving the car its rightful place without allowing it to dominate the city.

This reflects what can only be described as a seismic shift in thinking about traffic, brought about by the Dublin Transportation Initiative. And though the DTI got all its forecasts wrong, the process itself left an enduring legacy of enlightenment.

Through it the city's planners came to realise two essential truths - firstly, that the traffic problem could not be solved simply by throwing more roads at it and, secondly, that far too much of the public realm had been ceded to private cars, and the time had come to start reclaiming it.

In theory, of course, everyone could be conveyed into the city centre by car, but the cost would be massive urban blight and the wholesale demolition of historic buildings. Thanks to the DTI process, not even the most self-serving lobbyist for private transport would make that case any more.

"There's no doubt that the DTI brought about a huge sea-change in thinking," says Tim Brick, deputy city engineer in charge of roads. "We've made a conscious decision that we want the European model of a liveable urban environment, rather than the American model of car dependency."

Though their predecessors were seen as bogeymen, the city's current cadre of transport planners are probably ahead of the populace in their acceptance of the need for harsh measures; many Dublin drivers, caught up as they are in the "adolescent" phase of car ownership, have not thought things through quite as thoroughly and may, therefore, still subscribe to the old agenda of "predict and provide".

Unlike their counterparts in other European countries, most of them have not yet made a distinction between car ownership and use; they seem to believe that they have an automatic right to use their cars for any journey, however short, even when alternatives are available.

So how can the car, that ultimate symbol of the Me Generation, be tamed to make transport in Dublin and other urban areas more manageable? How can we, untameable people that we are, learn to accept a bit of regimentation, in the public interest? The answer to both is with difficulty and pain, particularly over the next five years.

Not even the most avid motorist could argue that the present situation works or, with any credibility, that the chaos on the streets can be sorted out by building more and more roads. Yet there are solutions that work which have been implemented elsewhere; what we need to do is to learn from them.

With travel demand in Ireland increasing at 7 per cent a year and car ownership levels rising relentlessly, we simply cannot go on the way we're going. "We should be moving into the `adult' phase now," John Henry, director of the Dublin Transportation Office, says, adding that every 1 per cent of commuters leaving their cars at home would save an estimated £25 million a year in congestion costs.

Astonishingly, official figures show that a quarter of all journeys during the morning peak are less than a mile - many of them school-runs. Even more telling is the fact that nearly half of all journeys within three miles are undertaken by car. That's a measure of how devoted we are to the cult of personal mobility, whatever about the congestion it creates.

What the figures suggest is that many Dubliners are within walking or cycling distance of their destinations. But even though they could easily do so, most commuters living in such inner suburbs as Glasnevin or Rathmines wouldn't stop using their cars; the only bikes some of them are likely to come in contact with are the stationary ones in a gym. In time, some of them may abandon their cars for mopeds, as many commuters are already doing, to get about town.

Is the writing on the wall for cars in the city? Almost two-thirds of motorists in Strasbourg said they believed that cars in towns are a thing of the past in response to a 1998 survey. Its mayor, Roland Ries, agreed: "The city does not belong to the car. Cyclists and pedestrians have more right to use the city."

Calling for political courage to deal with traffic, he said it was up to politicians to spell out what's at stake if unlimited car use continues and to propose alternative solutions. Otherwise, he warned, our cities will deteriorate into formless heaps with everexpanding sprawl.

The Government's decision in May 1998 to force LUAS underground between St Stephen's Green and Broadstone was perhaps the classic example of political timorousness; it was also made by Ministers who are accustomed to being conveyed in sleek black Mercs - on occasion travelling in convoy to the provinces.

There was also something ludicrous about the notion of politicians gathered around a table redesigning LUAS just hours before their shameful decision was announced. In opting to go under, they sabotaged the most important artery of the light rail project in terms of its civilising impact on the public realm through Dawson Street, Nassau Street, lower Grafton Street, College Green, Westmoreland Street and O'Connell Bridge.

Fears about the disruptive effects of constructing this crucial stretch were, and still are, irrational; other cities have endured the pain with no regrets; why is Dublin so different? It should also be borne in mind that the bridges designed by Santiago Calatrava for Macken Street and Blackhall Place are intended to provide a relief route for city centre traffic, and that the Corporation intends to go ahead with very painful plans to ban the left-turn from Dawson Street into Nassau Street, other than for buses and taxis, to reduce the volume of cars in O'Connell Street; this measure would also directly facilitate on-street light rail by removing much of the traffic along its originally-planned route.

With such a congenial operating environment in prospect, the proposal to put an essentially surface transit system underground is deeply flawed; the huge additional cost, with no return in passenger capacity, would be so utterly excessive and disproportionate as to make it barking mad.

The Construction of Dublin by Frank McDonald is published by Gandon Editions today, price £15