Police are searching for a witness after an elderly couple and their daughter were hit by a truck and rushed to hospital Saturday night.

Police said the family was crossing Main Street near, Bullock Drive in Markham, when they stopped to allow a northbound vehicle, believed to be an SUV or minivan, pass in front of them.

York Regional Police Const. Paul Diceman said a southbound pickup truck then struck the couple in their 70s and their daughter while they were on the road. The driver of the pickup truck stopped at the scene of the collision, he said.

It is believed that the driver of the other vehicle, suspected to be a silver or green SUV or minivan, may have witnessed the accident. Police are asking that they contact investigators.

Diceman said that rain and adverse weather conditions could have played a factor in the collision.

The mother, father and daughter were all rushed to hospital after the collision.

The father suffered head injuries and remains in Sunnybrook Hospital in critical condition. The mother sustained a broken leg, while the daughter suffered broken bones and a serious back injury.

With a report from CTV Toronto's Naomi Parness