A Greyhound bus carrying about 80 passengers left Interstate 39-90-94 near the Highway 151 interchange on Madison Far East Side and plowed though a fence Friday afternoon, injuring 17 people, state police said. The injured people were taken by ambulances from Madison and several surrounding communities to three area hospitals, all with non-life-threatening injuries, the Madison Fire Department said. State police were still investigating the cause of the accident Friday evening. The uninjured passengers waited along the highway and contended with heat and mosquitoes until transportation arrived, fire officials said. Two Madison Metro buses transported them from the crash scene to the bus station in Madison. The bus came to rest in a nearby field, police said. It moved off under its own power after the scene was cleared. Police and ambulances were called to the crash at 3:31 p.m., and by 4:50 p.m., all units had left, the Fire Department said.