How will people get in and out of the vast sports campus now being planned for Abbotstown? That is by far the most critical question overhanging the Taoiseach's grand project - and, despite yesterday's unveiling of a draft master plan for the 500-acre site, it is a question that the promoters have yet to answer.
Incredibly, the original feasibility study calculated that 45 per cent of the 80,000 spectators attending a major event at the proposed national stadium would travel to Abbotstown by car, generating a "requirement" for no less than 14,400 parking spaces - half of them on-site and the rest in an overflow car-park at Dunsink.
The draft master plan by German architects Behnisch and Behnisch, who designed the 1972 Olympics site in Munich, still envisages that at least 6,000 parking spaces would be provided on-site, plus a yet to be quantified number on the former Dunsink dump, which would be linked to Abbotstown by a bridge over the M50.
But the M50 is already congested at peak periods. Even if it is widened, as proposed, it would not have anything like the capacity to cope with a stormsurge of cars heading to and from, say, a rugby international at Stadium Ireland.
Gridlock on a grand scale, spilling over onto the N2 and N3, would be the inevitable consequence.
The M50 was supposed to provide a national bypass for Dublin. That's why the Dublin Transportation Initiative, in its 1994 final report, stressed the need to control commercial, retail and leisure developments along its corridor. And though the DTI report was adopted by the government of the day, it has been blithely ignored.
Nobody associated with the Abbotstown project appears to have read it, not even the Taoiseach, who was Minister for Finance at the time. Since then, the M50 has become a thoroughfare for "edge city" shopping centres, business parks and other major traffic generators. Abbotstown would cement this path of unsustainable development.
Without the parallel provision of a high-capacity, rail-based transport system, it simply will not work. Yet transport is the weakest link in the package unveiled yesterday. All it says is that a transportation policy is "currently being developed" and that it would involve providing "a substantially improved infrastructure" for the area.
Consultants are believed to be examining the option of a rail spur from the Sligo line, which would serve Blanchardstown shopping centre, James Connolly Memorial Hospital, the nearby institute of technology and the Abbotstown site, where three metro stations are indicated on the draft master plan, with a terminus at Dublin Airport.
OPTIMISTS such as Laura Magahy, who is supplying executive services for Sports Campus Ireland Ltd, the State company planning Abbotstown, believe it will act as a "trigger" to fast-track the sorely needed airport rail link. But this would mean supplanting the DTO's longer-term plan for a metro line from Sandyford to the airport.
Stefan Behnisch, whose Stuttgart-based firm won a competition for the Abbotstown master plan, said the 1972 Olympics provided the impetus for Munich to upgrade its public transport system - and he was convinced the same would happen here.
He sees Abbotstown as a "people's park" rather than just a venue for sports fans. The major facilities would be disported alongside an artificial lake in the middle of the site, linked together with a series of emblematic covered walkways, with extensive parklands retained to the south and a still notional "athletes' village" to the north.
The draft master plan is to be fleshed out in detail by June, in tandem with the selection of an international consortium which would deliver Stadium Ireland and the various other facilities on a DBFOM (design, build, finance, operate and maintain) basis. But it is clear that Abbotstown will cost the Exchequer at least £450 million.
The seven competing consortiums, all of them from overseas, are required to select their architects from two panels drawn up by Sports Campus Ireland. Those in the running for the stadium include such superstars as Jean Nouvel, Dominique Perrault and Richard Rogers as well as the lesser known Paul Andreu (with Murray O'Laoire).
Scott Tallon Walker is the only Irish practice on the list for the 15,000-seat indoor arena, which also includes British architects Nicholas Grimshaw and Michael Hopkins and several continental firms. But Irish practices feature strongly on a second panel for smaller projects, including all the members of Group 91, the architects of Temple Bar.
Though the Abbotstown promoters are committed to "architectural excellence", the DBFOM procurement method is fraught with dangers because it effectively puts the contractors, rather than the architects, in the driving seat. Great care will need to be exercised to ensure that design concepts are not compromised in the process.
This concern is shared by Stefan Behnisch. "But I think we have a client who understands this problem and we have picked architects who are sure to assert themselves," he said. "If you start high with a very strong concept, you'll get something good. And with stadiums and sports halls, it's not a question of detail but of concept."