A York County truck driver is killed in Berks County when a large rock crashes through the windshield of his tractor trailer rig. State police believe the incident that claimed the life of Ronald L. Hengst of Spring Grove RD1 is tied to independent truckers' calls for a strike to protest gasoline prices. The rock, dropped from an overpass, causes Hengst's truck to run off the road and down an embankment, where it overturns. Police consider the incident a murder and assign 10 troopers to the case. The incident prompts Pennsylvania Gov. Milton J. Shapp to activate the National Guard to help state police the free movement of trucks.