Dublin Bus wants plans for the College Green plaza halted until it caries out its own review of services.
Planning consultant for the bus company Ann Mulcrone told a Bord Pleanála hearing that nobody wants a repeat of the unforeseen problems following the introduction of the Luas Cross City.
The five-day hearing by An Bord Pleanála on a plan to create a pedestrianised plaza began yesterday.
She said Bus Connects - the current review of services - is a "necessary prior analysis to this project".
Ms Mulcrone pointed out that Dublin Bus accounts for 72% of people travelling in the city centre during the 4-7pm rush-hour.
She said buses are essential for access to the city centre and the area around College Green is an area of high demand.
Ms Mulcrone said that rerouting buses both ways on Parliament Street is "the least worst option".
Diverting northbound buses through Winetavern Street would not meet demand, she said.
The National Transport Authority also wants two-way public transport on Parliament Street.
Deputy Chief Executive Hugh Cregan said the National Transport Authority's support for the project is contingent on having a new 24-hour public transport northbound lane on Parliament Street.
The NTA also wants a new northbound lane on Capel Street Bridge allowing a right-hand turn onto Ormond Quay.
The southbound lane on Parliament Street would only be restricted to public transport during weekday hours.
Mr Cregan also said that the 100,000 pedestrians who use College Green every day are often ignored or overlooked.
Council does not intend to allow two-way Parliament Street traffic, hearing told
Meanwhile, Dublin City Council has said it does not intend to allow two-way bus routes on Parliament Street despite submissions from the NTA and Dublin Bus.
Both the NTA and Dublin Bus have called for north, as well as southbound, bus journeys on Parliament Street as part of new traffic arrangements for the College Green plaza.
A number of southbound bus routes would be diverted from College Green to Parliament Street as part of the city council plan.
Northbound buses would be diverted through Winetavern Street at the Western side of Christchurch but Dublin Bus says this is too far away from the city centre.
Donal McDaid of engineering consulting firm Arup told the An Bord Pleanála hearing that the city council had decided against the two-way buses idea because of air quality concerns.
The NTA has asked for low-emission vehicles to be used on Parliament Street but Mr McDaid said the council is not a regulator of the bus fleet.
In reply to concerns about impacts on Parliament Street Mr McDaid said overall traffic would be reduced by 61% daily as it would be made public transport only during weekdays.
There would be a new left turn allowed from Wellington Quay.
He said a predicted increase in 12 HGVs including buses during the hour peak is "negligible" considering the overall reduction in traffic.
Earlier, the council's Head of Technical Services, Brendan O'Brien, told the hearing that the rerouting of 100 buses per hour had not eliminated delays, which also affect pedestrians and cyclists.
The longer-term solution to traffic problems at Dublin's College Green is to remove east and west traffic movement, according to the council.
Mr O'Brien said that north and southbound Luas trams cannot pass College Green simultaneously because of traffic turning onto Dame Street.
A ban on taxis travelling southbound between 7am and 10am Monday to Friday came into effect yesterday.
Mr O'Brien said that the longer-term solution is removing conflicting movement and allowing a "fast and efficient" corridor running north and south for trams, buses, taxis and cyclists.
"This would change the operation of the Trinity junction so that trams in both directions can run at the same time and will no longer impede each other".
He said it would also benefit bus services and allow taxis to now travel northbound through the area.
Pedestrians and cyclists would also benefit from reduced waiting times.
Earlier, consultant engineer Seamus Mac Gearailt told the oral hearing that three bus routes that currently terminate at Dame Street will have a turning circle at the western end of the plaza.
It is estimated that seven buses an hour would u-turn here in a circle area that has been tested at the Dublin Fire Brigade Training Centre.
Mr Mac Gearailt said the plaza would be 90% pedestrianised with a two way cycle track at the southern edge and clear guidance for the visually impaired through corduroy paving or cobbled channels instead of kerbs.
Hotels want taxi route through Temple Bar to be considered
Dublin's top hotels want a taxi route through Temple Bar to be considered if the College Green plaza gets the go ahead.
Paul Chandler, an engineer representing six five-star hotels, said Anglesey Street and Fleet Street could be opened up to allow a South to North route that would bypass College Green.
The hotels - the Fitzwilliam, Marker, Merrion, Shelbourne, Westin and Westbury - also want taxis to be able to use Parliament Street both ways.
Kieran Doohan, representing the Westbury, said the six hotels employ 1,800 people, generate €150m in sales a year and pay €1.8m in rates.
He said delays in taxi services, which are used by up to 80% of hotel guests, could mean Dublin losing its appeal to international event organisers.
Charlie Sheil, representing The Marker, said congestion near Macken Street Bridge can already mean a 1.5km journey taking 40 minutes.
He said it was feared that the College Green project could displace more traffic and cause more delays.