MUDDY CREEK TWP — A suspected drugged driver was seriously injured Monday afternoon when she crossed the Interstate 79 median and collided head-on with a tractor-trailer, state police said.

A medical helicopter flew Cassandra R. Kowalski, 21, of Ambridge, Beaver County, to Allegheny General Hospital in Pittsburgh following the wreck about 3:05 p.m.

Kowalski suffered severe head injuries, said police Lt. Eric Hermick. Investigators suspect she was impaired by prescription medication.

Police said the woman was southbound on I-79 when she lost control of her car and drove through the median, colliding with the northbound rig.

The truck driver’s name was not available.

Hermick said charges including driving under the influence of a controlled substance are pending against Kowalski. Her condition was not known this morning.

Portersville and Harmony volunteer firefighters assisted police at the scene.