Dublin City Council has backed Dublin Bus and blamed Luas for breaching agreed protocols and causing last Tuesday morning's unusually bad traffic congestion in Dublin City Centre.
The city council's director of traffic, Mr Owen Keegan, has said he was "certain, absolutely satisfied, that there was a major problem with the operation of the signals due to Luas".
Mr Keegan said the problem "needs to be sorted out" because "it does have the potential to have a disproportionate impact on traffic congestion and that's not acceptable to the city council".
While Mr Keegan said he accepted that Tuesday's torrential rain was a significant factor in the congestion, Dublin Bus yesterday produced satellite photographs of the city centre which the company claimed indicated the downpour had not occurred at the time the delays started and were most severe.
Dublin Bus also claimed the delays were caused on a morning when traffic was not especially heavy, as it was the summer season and senior schools were closed.
The bus company is also concerned that what happened on Tuesday morning was the result of the Luas priority system being in use on just one junction, St Stephen's Green.
While a spokeswoman for the company claimed the "only interest of Dublin Bus is to ensure the traffic flows for everybody", company sources said "the key questions are what priority does Luas have and will it be used whenever they like.
"If it is, what happened on Tuesday morning will happen all over the city."
Luas and Dublin City Council traffic personnel were meeting until late in the evening yesterday but earlier Mr Keegan described the operation of the Luas priority system on the Dublin radio station Newstalk: "Basically it is a facility that was there to be used in very limited circumstances, where if a tram misses a green signal it can put in a request to expedite the next green." Mr Keegan said there was low, medium and high priority for trams approaching a traffic signal, but it was "a matter really for the city council to decide, and to what extent priority will be given".
The Railway Procurement Agency (RPA), which is installing the Luas system, has said the problem was a "glitch" which occurred under test conditions and which would be fine-tuned. The glitch appears to have resulted in the city council traffic controllers being unable to "downgrade" Luas requests for high priority.
However, Mr Ger Hannon of the RPA accused Dublin Bus of operating in a "curious way" because it says the first it knew of a complaint from the bus company was in an article in The Irish Times yesterday.
The RPA's Mr Tom Manning later said "there are glitches in the system which we are eliminating.
"That is why we are having the testing period. In the vast majority of cases this couldn't happen. It is a teething problem."
