Two new rock throwing incidents took place on Interstate 35, Sunday.
Police say, in the first incident, a Williamson County EMS ambulance was hit by a rock. It happened at 12300 N. I-35, near Tech Ridge Boulevard/Yager Lane, at 1:20 a.m. Williamson County says there were two EMTs in the ambulance at the time of the incident, but no one was injured. The ambulance was returning to Hutto after dropping off a patient in Austin.