A woman was injured Tuesday morning when she was thrown from her van as it rolled after she lost control on the bypass.The victim, Shawna Mason, 35, was airlifted from the scene by LifeForce helicopter to Erlanger Medical Center in Chattanooga.The wreck happened around 7 a.m. Tuesday on Highway 55 Bypass near its intersection with Shangri La Lane just outside McMinnville city limits.According to highway patrolman Bruce Pryor, the wreck was a one-vehicle accident and involved Mason losing control for unknown reasons. A preliminary investigation revealed Mason was heading eastbound, toward town, when she ran off the right side of the road.She then came back onto the highway and crossed over both eastbound lanes before her 1997 Ford Aerostar went into a sideways slide and entered the downward-sloped median. The change in slope, combined with the slide, caused the van to roll and eject Mason onto the median.