The chairman of CIÉ has said the company intends to publish the findings of its inquiry into Saturday's accident, in which five people were killed on Wellington Quay, in six weeks' time.
John Lynch said an inquiry team had been formed and would meet on Friday.
He said the two drivers involved in the accident were receiving counselling but were not expected to be back driving in the short term.
He said the company knew what had happened but did not know why it had happened.
Meanwhile, Dublin Bus has opened a Book of Condolence at its headquarters on O'Connell Street in Dublin. The Taoiseach, Bertie Ahern, and the Minister for Transport, Seamus Brennan, were among the first to sign the book.
Speaking earlier on RTÉ's Morning Ireland, Dublin Bus Spokeswoman, Gráinne Mackin, said the number 66 bus was five feet from the kerb picking up passengers when the second bus ploughed into them.
She also said the accident was not caused by a medical problem with either of the drivers. Ms Mackin said the inquiry - which will involve international experts - would look at every possible cause.
Earlier, the five people killed were named as Kevin Gary, 43, from Leixlip, Vasul Tyminsky, 33, a Ukrainian living in Lucan, 59-year-old Margaret Traynor from Darndale, Kathleen Gilton, 69, from Maynooth, and 43-year-old Theresa Keatly from Ballymun.
Post mortem examinations have now been carried out on the victims' bodies.
Dublin Bus has organised a team of counsellors to help the families of the bereaved as well as staff members and eyewitnesses.
Dublin Bus has denied that the bus stop on Wellington Quay was unsafe. It was moved from Middle Abbey Street 18 months ago because of Luas works.