Dr Garret FitzGerald may well have been a 1960s pioneer in advocating urban road pricing, as he recalled in his column last Saturday, but his championship of the option of putting Luas underground directly contradicts the position he adopted just over a decade ago. For it was in 1986, while Taoiseach, that he ruled out any form of mass transit as a way to deal with Dublin's traffic chaos.
Addressing the Dublin Crisis Conference in February 1986, Dr FitzGerald conceded that "the failure to develop public transport" was the main factor in encouraging "a level of private transport which is quite disproportionate to our stage of development". However, he said the "extremely low density" of Dublin's suburbs made the city "quite unsuited to mass transportation". As a result, he declared, "transport has to be by buses rather than mass transit, for the greater part".
That is one of the reasons why CIE was unable to implement the 1975 Dublin Rail Rapid Transit Study, which recommended a "heavy rail" mass transit system serving Tallaght, Blanchardstown and Lucan/Clondalkin, with an underground line in the city centre and a central station under the Liffey between Temple Bar and Ormond Quay.
The DART, between Howth and Bray, was the first - and, as it turned out, the only - phase of this hugely-ambitious project. The rest of it was scrapped on cost grounds in 1987 by the then Fianna Fail government.
And as for developing the proposed central station - a bus/rail interchange with office blocks, shopping malls and a hotel overhead - that idea was firmly knocked on the head by Mr Charles Haughey in the same year when he described Temple Bar as "one of the most important, traditional, historic, attractive and interesting parts of Dublin" and memorably declared that he "wouldn't let CIE near it".
Ten years later, courtesy of Ms Mary O'Rourke and unrelenting pressure from the car lobby, we're back looking into an underground yet again - despite everything that's happening abroad where on-street light rail is the preferred option for urban public transport and hardly any cities are planning to go underground.
Indeed, as I recently noted, the French city of Lyons decided recently that a 20-kilometre extension to its new metro would be built on-street - not least to save money.
MR Tom Koenigs, deputy major and finance officer of Frankfurt, once told me that his biggest regret was that the city had opted to go underground many years ago. If he had his way, the city's public transport lines would be raised to street level as a light rail transit system.
In his view, not only is an underground less pleasant and secure for users, but it also requires substantial additional expenditure to keep every underground station manned during its hours of operation.
As an economist, Dr FitzGerald must take such considerations on board and make allowances for the fact that on-street light rail, with its stops rather than stations, does not require similar manning levels. But he prefers to concentrate on the issue of capacity - whether Luas, as proposed, would be physically capable of catering for passenger demand.
I wouldn't claim to have Dr FitzGerald's facility for figures but it seems to me that this is something of a red herring.
According to the multi-volume environmental impact statement on Luas, the system now being proposed would have an initial carrying capacity of 3,000 passengers per hour each way on the Tallaght and Dundrum lines. This is not something which is fixed; it could be expanded by having longer trams (40 metres as against 30 metres) and ordering more of them. The extra cost of doing that - and it should be done - would be much less expensive than putting Luas underground.
Last Saturday, Dr FitzGerald suggested that those of us who favoured Luas had some "nerve" in suggesting that his advocacy of the underground option made him virtually a card-carrying member of the car lobby.
I have never made that case. However, I would maintain that his campaign to put Luas underground in the city centre has - no doubt unintentionally on his part - provided much grist to the mill for those who are determined to preserve road space in the city for private cars.
Unlike them, Dr FitzGerald believes that we should have urban road pricing as a tool to reduce traffic congestion, particularly at peak hours. During a 1989 Dail debate he pointed out that parking controls alone would not solve the problem, which was caused by the free availability of road space. "If champagne were free, it would be over-drunk," he said. "If a valuable product is made available free of charge, people will use it and abuse it to the point of grossest economic distortion."
I agree with him 100 per cent that car commuters should be charged a fee for entering the city at peak hours, by electronic "tagging" or some other means, to reflect the true social cost of the congestion they create. This might encourage many of them to leave their private chariots at home and take public transport. And if that were to happen, as Dr FitzGerald argues, it would free up valuable road space in the city and make the operation of its public transport system more efficient.
WHERE we part company is that I believe that the best possible use of such freed-up road space would be to dedicate it to public transport on a permanent basis. Because if it is not used to make room for an on-street Luas system, it will continue to be occupied by cars and other traffic, as Ireland's car ownership rates are driven upwards by increasing prosperity towards the European norm.
But even without road pricing, we need to reduce, rather than increase, the space available for cars. Take Amsterdam, for example. True, it has a metro, but the majority of public transport trips in the city are made by tram.
And Damrak, one of its main streets, consists of two wide footpaths, flanked by two wide cycleways, with a pair of tramlines in the middle and one lane for cars.
This is the kind of conscious choice about the allocation of space on urban streets which is made by a country - the Netherlands - which has a population of 15 million and no less than six mil- lion cars. The Dutch have chosen not to allow their cars to dominate their cities and the civilising impact is visible to all.
Mr Cathal MacCoille, the RTE journalist, wrote to me about the strong impression his first visit to Amsterdam made on him. Suddenly, he had "a sense of knowing vividly what Frank McDonald has been on about all these years" as he noticed the "body language and facial expressions of people moving about in a city designed to cater for them instead of the demon car".
That, surely, is the way to go.