Police say 50-year-old Duane C. Woodson of Pittsburgh crossed into the opposite lane and collided head-on with a vehicle driven by 45-year-old Christine Beilstein, of Plum, who was pronounced dead at the scene.
Her 9-year-old son was flown to Children's Hospital of Pittsburgh and was in critical condition with a severe head injury late Saturday night.
Police say Woodson attempted to flee the scene on foot after the crash but was apprehended.
A judge denied bail and Woodson is being held in Allegheny County Jail.
No attorney was listed on court papers.