WALTHAM, MA - On the evening of January 28th, two cars collided at Main and Stow Streets in Waltham. One car had rolled over on its side. Waltham Engine 4, Rescue 1 and Medic 1 responded. The operator of the car that rolled over needed to be extricated. That person was transported to Lahey Trauma Center, the other operator went to Newton Wellesley Hospital. A bystander refused medical attention.