An 83-year-old woman is in hospital with serious, life-threatening injuries after she was hit by a vehicle reversing out of a driveway in Hamilton's east end on Monday afternoon.

Police arrested and charged the 31-year-old driver of the vehicle, saying he was over the legal alcohol limit.

The collision happened around 4 p.m. The driver and other witnesses tried to help the woman while paramedics were on their way, police say.

The police Collision Reconstruction Unit is still investigating.