LYNN – A man was seriously injured and rush-hour traffic on Western Avenue shut down for several hours Wednesday afternoon after a van rolled over near the Lynn-Salem border.The unidentified driver of the vehicle, a red Chevrolet van, was traveling alone down Western Avenue at about 5 p.m., when, for unknown reasons, the van flipped over, according to Lynn Police Lt. Mike Vail.Lynn and State police as well as fire and rescue crews responded to the scene and helped pull the man from the van. Police said the victim was conscious and alert after being partially ejected and re-trapped in the van, which was laying on its side.He was taken by ambulance to Lynn English High School to meet up with a MedFlight helicopter, which transported him to a hospital in Boston.Police closed Western Avenue leading into Highland Avenue at the Lynn-Salem border for most of the evening and re-routed traffic traveling south from Salem, Vail said.Police have not identified the victim and no updates on his condition were available.Taylor Provost can be reached at [email protected].