1969 Pennsylvania Turnpike shootings
On April 5, 1969, Donald Martin Lambright, son of comedian Stepin Fetchit, was traveling along the Pennsylvania Turnpike, east of Harrisburg, Pennsylvania, when he went on a shooting spree. Reportedly, he injured sixteen and killed four, including his wife, with an M1 carbine and a .30-caliber Marlin 336 carbine, before turning one of the rifles on himself.
Source: Wikipedia — 1969 Pennsylvania Turnpike shootings (CC BY-SA 4.0)