How did we walk - or, rather, drive - ourselves into this awful mess? After a century-long love affair with the car, traffic is moving at about the same speed as it was in the era of the horse and cart. The very proliferation of automobiles, as Americans call them, has set aside the promise that they would give us all freedom of movement.
According to Mr John Henry, the DTO's director, we failed to appreciate that there was a crucial link between land use and transportation. Like other Irish cities over the past 30 years or more, Dublin was developed at a particularly low density of just six to eight houses per acre, with little or no reference to the availability of public transport.
"Land use is where it all started to go wrong," Mr Henry said. "We put industrial estates here and residential estates there in separate single units; Tallaght is a good example. We moved the people out and they had to travel back to the jobs, but then, we all wanted our own semi-d with front garden, back garden, a sense of home and place."
Dublin has the same population as Copenhagen, but it occupies about double the land area of the Danish capital, and it is precisely because Dublin is far from compact that we now have a transport crisis. The city was not designed to facilitate public transport, which would have required higher densities along rail or high-capacity bus routes.
Most motorised Dubliners have also failed to make any distinction between car ownership and car use. The Netherlands, for example, has 15 million people and more than six million cars - yet its cities are not choked by traffic because most Dutch people do not use their cars to get to work, relying instead on excellent public transport systems.
Despite the Government's endorsement of higher housing densities, land is still being rezoned in the Dublin area for car-dependent low-density development. Fingal County Council even voted down a Green Party motion that the shopping centre planned to serve a new community north of Baldoyle should be located beside a DART station.
Antediluvian attitudes persist. Some pro-motoring pressure groups still believe we can build our way out of the problem, with such expensive schemes as the Eastern Bypass. Senator Brendan Daly (FF) has even suggested that pedestrians should be put underground at key junctions in the city to free up the movement of traffic.
Yet at any time of the day or night, as Mr Keegan keeps pointing out, there are more pedestrians on the city's streets than cars. Other European cities have also found sensible ways to tame the traffic, and this series will be exploring some of the novel ideas they have adopted in recent years.
Belfast, Cork, Limerick, Galway and Waterford, together with many provincial towns, are also suffering from the effects of increasing car use. The series will concentrate on Dublin, because that's where the problem is at its most acute, but the solutions it will put forward should be of interest to transport users and planners everywhere.