The case for introducing congestion charges to control Dublin traffic is a strong one. For, it is abundantly clear that Dublin traffic has been seriously congested since the late 1990s, and unless we can return to the scale of commuter car traffic (including children brought by car to school) that existed around 1997, the city will continue to face frustrating and costly congestion.
Some people argue that all that is needed is to improve our public transport system and, in particular, the bus services. But the principal problem with our Dublin bus system is that, even with bus corridors on some roads into the city, the ever-increasing volume of car traffic prevents buses from operating efficiently. Our bus fleet has been greatly enlarged in recent years, but much of this extra capacity is being used simply to carry a given number of passengers ever more slowly.
Until the volume of private car traffic is substantially reduced, we cannot have an efficient bus service.
We are indeed in a vicious circle. Commuters will not transfer to buses because on so many routes the service is slow and unreliable - and the service is slow and unreliable because there are too many cars on the road to allow buses to operate efficiently!
The reason why this is the case is that one of our most valuable national assets - urban road space - is made available to motorists free. Of course, urban as well as rural motorists can claim to pay for roads generally, through road tax and petrol taxation.
But that burden is not equitably shared between urban and rural dwellers, for, whilst urban motorists may have to pay a bit more per mile in the form of petrol tax because of having to drive at uneconomically low speeds with much stopping and starting, their payments do not cover more than a fraction of the actual value of the road space they are occupying - especially as only one out of five commuting motorists carries a passenger, and only one in 15 carries more than one passenger.
By contrast, most rural car drivers use much less valuable road space, and more of them tend to carry passengers. By any standards their motoring is over-taxed in relation to the value of the road space they occupy and the very limited congestion costs they impose on other road users.
Once urban motorists possess a car, the marginal cost of using it for commuting to and from the city is a tiny fraction of the costs that they impose on others as a result of being allowed to occupy valuable road space at much less than its value. In commuting, as in everything else, goods and services offered free or below cost rapidly become in short supply.
The clear answer to this problem lies in devising a method of charging for urban road space, especially at peak times, which will reduce excess road demand and thus facilitate bus operations. This would encourage many currently frustrated car commuters to get to and from work more quickly by public transport.
It is possible to calculate the approximate scale of this problem. In 1997 there were some 180,000 peak commuter journeys in Dublin each week-day by car.
Today this figure has probably increased by one-third to about 240,000, and it is these 60,000 extra cars on the road that have created our present traffic crisis.
The Dublin Transportation Office has estimated that even if public transport were expanded to two-and-half times its present scale, (which is as much as they believe can be done on the basis of existing public transport investment commitments), this peak car commuting figure would nevertheless rise to about 315,000.
That figure would be three-quarters higher than that of 1997. With that level of car commuting it would, of course, be impossible even for the present bus fleet to operate effectively - never mind the much larger fleet predicated by the DTO.
It is, of course, possible that the DTO peak commuter forecast for 2016 may be somewhat on the high side. But it is difficult to see how, on the basis of any plausible assumption that can be made, peak traffic could fall short of the DTO projection for 2016 by more than perhaps 10-12 per cent - and as the growth of peak traffic is likely to continue after that date, within a few years thereafter the forecast would in any event be validated.
Thus on the basis of the public transport commitments entered into before the DTO Report was prepared, which the DTO says would increase today's Dublin bus capacity by three-fifths and commuter rail capacity two-and-a-half times, there would remain a volume of private car commuter traffic significantly greater than that with which we are currently failing to cope;
The truth is - and it is a truth that needs to be faced by Government and Dublin motorists alike - without some system of congestion charging combined with the construction of Metro lines serving major suburbs, Dublin will simply seize up at some point during the next dozen years.
If anyone doubts this, let them argue their case in the only valid way in which it can be seriously debated - namely by contesting with plausible arguments the traffic flow projections published by the DTO.