A 64-year-old Wallenstein woman remains in a Hamilton hospital with life-threatening injuries after her minivan collided with a school bus full of children.  Friday morning, the investigating officer says the woman's condition has been upgraded to stable.

It happened shortly before 9 a.m. Thursday on Ament Line near Hawkesville.

Waterloo Regional Police say the bus was stopped to pick up a student when the van crashed into it from behind, becoming wedged into and underneath the bus.

There were 17 students on board the bus at the time, on their way to St. Jacobs Public School.

Three of the 17 reported minor injuries following the crash. All three were examined at the scene by paramedics.

“They’re fine now,” school principal Kathy Mathers tells CTV News.

“We are really fortunate that all of the children were sitting how they should have been on the bus.”

A second school bus was brought in to take the kids to St. Jacobs for the last day of class before March Break.

“They were all anxious to get back to the regular routines,” says Mathers.

Police say two vehicles stopped behind the crash and left the scene before police arrived.

“We’d like to speak to those two witnesses, if they would come forward,” says Sgt. Stu Church.

Ament Line remained closed until late afternoon.

An investigation into the crash revealed all the lights and signals on the school bus were working and the stop arm was out at the time of the crash.