Three St. Charles County residents were injured, one seriously, in a crossover crash on Interstate 70 in Warren County.The 4:45 p.m. crash happened Wednesday, Aug. 10, on eastbound I-70 at the 197.6-mile marker, the Missouri State Highway Patrol reported. Mackenzie R. Brelsford, 17, St. Peters, was driving a 1999 Honda Accord eastbound when she swerved to avoid an unidentified vehicle, according to the report. The Brelsford car struck a 1997 Chevrolet K-1500 driven by Michael J. Cullom, 33, Warrenton, then ran off the right side of the road.Brelsford then steered back onto the road, overcorrected and ran off the left side onto the grass median, struck a concrete drainage and drove through an emergency crossover, according to the preliminary patrol report.Brelsford’s car then collided with a westbound 2006 Ford F-350 driven by Steven E. Rollins, 56, Wake Forest, S.C., and then was struck in the left side by a 2012 Freightliner tractor-trailer driven by William R. Haddix, 70, Lexington, Ky., the patrol reported.Brelsford was seriously injured in the crash and was transported by air ambulance to Mercy Hospital St. Louis, Creve Coeur.Two passengers, Mikayla A. Baker, 16, and Emilia C. Haungs, 16, both of St. Peters, were taken by Warren County EMS to St. Joseph Hospital, Lake Saint Louis, for treatment of moderate injuries.All drivers and passengers were wearing safety belts, the patrol reported.MVA