A woman was trapped in her Jeep Monday morning after a semitrailer caused her to crash into a tractor near Hebron, according to authorities. The semitrailer was traveling north on Greenwood Road, south of Tryon Grove Road, when it rear-ended a Jeep Cherokee that was following a slow-moving farm tractor towing a water tank, McHenry County Sheriff's Office Spokeswoman Sandra Rogers said. The impact caused the Jeep to strike the tractor, and the semitrailer crashed into a ditch.