The crash: The driver of the school bus in Monday afternoon's accident near Navan was discharged from hospital yesterday following overnight treatment for his injuries.
Two cars, a black BMW and a silver Opel Corsa, were also involved in the accident.
The driver of the BMW was still in intensive care in Our Lady of Lourdes Hospital, Drogheda, Co Louth, last night. Her injuries were said not to be life-threatening.
The driver of the Opel Corsa was discharged from hospital yesterday.
A lorry and another car in the immediate vicinity at the time of the accident were not in collision with any other vehicles, and their occupants were not injured.
One of the young people travelling on the bus, 16-year-old Mark McCabe, yesterday recalled the moment of the accident.
"I just remember everyone flying through the air. One of my friends went through the back window," he said.
The stretch of road on which the accident happened between Navan and Kentstown was undergoing resurfacing work, and temporary traffic lights were in operation on a 200-metre section, about 4km from Navan.
Single-lane traffic was in operation on this section between the two sets of temporary traffic lights.
Workmen using heavy plant machinery were resurfacing one side of the road which was closed to traffic.
The accident took place immediately on the Navan side of this single-lane section.
The road was wet at the time of the crash from heavy localised showers.
The stretch of road features a number of sweeping bends and a speed limit of 80km/h.
Senior Garda sources last night said the exact circumstances of the crash could be known as early as today when the drivers of the three vehicles have been interviewed.
Detectives were hopeful that the driver of the Opel would be well enough to be interviewed late last night.
At least five of the 46 surviving schoolchildren were being interviewed last night by detectives at Navan Garda station, where the Garda inquiry is based.
Garda sources said that, while witness statements would prove vital, all the physical evidence at the scene, as well as the three vehicles, would be closely examined.
Gardaí said they would consider what contributory role, if any, the smooth wet surface had played in the crash.
The speed at which all the vehicles were travelling would also be examined, as would the location of any street furniture in the vicinity.
This includes the location of the temporary sets of traffic lights in relation to bends in the road and the location of a traffic light warning sign which would have been passed by the school bus immediately before the accident.
The three vehicles were taken by gardaí from the scene yesterday. A full examination will be carried out on them.
Members of the Garda Technical Bureau carried out a full examination of the scene yesterday.
Inspectors from the Health and Safety Authority also carried out a series of tests and recorded the crash scene using special car-mounted cameras.
Investigators from Bus Éireann are conducting a third investigation.
The Garda operation involves Navan-based gardaí backed by members of the National Bureau of Criminal Investigation. It is being lead by Chief Supt Michael Finnegan.
The stretch of road where the accident occurred is on the R153 from Navan to Kentstown.
A 4km stretch of the road was being resurfaced at the time by Lagan Asphalt Ltd, Dublin, on behalf of Meath County Council.
When contacted by The Irish Times last night Lagan Asphalt said all of its staff "joined the wider community in expressing their deepest sympathy with the families of those who died or were injured".
The company said it would be inappropriate to speculate on the causes of the crash in view of the fact that there were three separate inquiries under way.
A spokesman said that the firm would be co-operating fully with these investigations.
