Dublin Bus has said it will publish the findings of its inquiry into Saturday's bus crash, in which five people were killed in Dublin City centre, in six weeks.
The Taoiseach, Mr Ahern, at the scene of the bus crash on Wellington Quay yesterday
The company's chairman Mr John Lynch said a four-person inquiry team had been formed and would meet on Friday.
The company's board held an emergency meeting today and are expected to announce that experts from Britain, Germany and Sweden will assist in establishing the cause of the crash.
A company spokeswoman said: "People want answers about what happened, and so do we."
Dublin Bus today ruled out speculation that a medical problem such as the bus driver having a heart attack might have led to the crash which also left 20 people injured, some seriously. The injuries are not life-threatening.
Dublin Bus has set up a family liaison team to deal with the aftermath of the accident and has made bereavement counsellors available to help victims of the accident. It has also offered to meet the medical costs of victims.
The crash happened on Wellington Quay on Saturday afternoon when an out-of-service Airlink bus, which appeared to be out-of-control, mounted the pavement and crashed into passengers queuing to board a number 66 bus.
Fine Gael transport spokesman Mr Denis Naughten
Dublin Bus this morning opened a book of condolences at its offices in O'Connell Street. The Taoiseach, Mr Ahern and the Minister for Transport, Mr Brennan, were among the first to sign.
After adding his signature to the book of condolences - as a pile of wreaths built up at the Wellington Quay scene of the crash - Mr Ahern again expressed his sympathy for the families affected by the deaths.
Mr Brennan cautioned against seeking a "quick answer and a simple solution" to what had happened. "There is always a temptation to look for an immediate explanation," he said.
"This has been a terrible accident and created terrible trauma. But we should be cautious about trying to take some easy solution off the shelf when there isn't one."
The minister will face questions in the Dáil this week about the incident. Fine Gael transport spokesman Mr Denis Naughten said he will ask the Minister to elaborate on the investigations taking place and outline the circumstances surrounding the accident.
He added: "I also want to establish what information, if any, was provided to the management of Dublin Bus concerning the safety of this particular bus-stop, which could have averted the incident or at least reduced the level of fatalities."
Safety concerns had been raised at a meeting between Dublin Bus and local councillors less than two weeks ago.
Mr Catherine Murphy, chairwoman of the traffic and transport committee of Leixlip Town Council, in Co Kildare, confirmed she had highlighted the "unsatisfactory" bus location at Wellington Quay with bus company executives.
One of the buses involved in the accident, the number 66, which serves the Leixlip area, originally terminated in Abbey Street but was recently re-sited to make way for work on the city's new Luas light transport system.
Ms Murphy said her council had been told that Dublin Bus was unhappy at the new location and planned to move it again later this year.
"The unsatisfactory nature of the terminus at Wellington Quay was one of the items on the agenda at our meeting with Dublin Bus earlier this month," she said.
"It is confined to a much tighter space than in its previous location, and people had concerns about personal safety.
"At peak times, people had to push through, but I don't really think you could have predicted the accident that has happened, and the awfulness of it. "
Meanwhile, Gardaí are expected to interview both bus drivers today, in the belief they can provide information surrounding the worst accident in the history of Dublin Bus.