About 5:55 p.m. on April 20, 1981, a scheduled intercity bus with 34 passengers on board was southbound on Interstate Route 95 (I-95) en route to Washington, D.C., via Silver Spring, Maryland. As the bus approached the Interstate Route 495 (Capital Beltway) interchange, the traffic ahead in the right lane slowed and came to a stop. The bus failed to stop, crashed into the rear of the automobile ahead of it, and precipitated a four-car, front-to-rear-end collision. Two of the automobiles burst into flames which quickly spread to and engulfed the bus after it had been evacuated. Three occupants of the automobile struck by the bus were killed. The drivers of the other three automobiles, the busdriver, and the 34 bus passengers received minor injuries.