A Knoxville woman was transported to Mercy Hospital in Des Moines by helicopter on Friday after her vehicle was struck by a semi.

According to a report from the Iowa State Patrol 18-year-old Bridget Helle was driving eastbound along Highway G71 in Mahaska county when a semi turned onto the highway from a private drive. Helle struck the rear of the semi. The semi driver was unhurt. The crash is under investigation by the Iowa State Patrol. Mercy Staff tell KNIA/KRLS News her injuries are serious but she is in fair condition.