It happened just before 5 p.m. near Cedar Hill Road in Lower Gwynedd Township.
Police tell Action News a shooting occurred after officers responded to reports of a disabled vehicle at Welsh Road and Bethlehem Pike.
The view from Chopper 6 showed a gun on the highway, at least one shell casing and a victim covered by a tarp.
According to Pennsylvania State Police, a man suffered a fatal self-inflicted gunshot wound on the highway.
Further details on the shooting have not been released.
Rt. 309 from Welsh Road to Norristown Road reopened just before 9:30 p.m.