P was struck on the head by a chunk of concrete thrown from a freeway overpass by two juveniles. P was driving a 1984 Chevrolet Corvette recently purchased by his girlfriend, Jane Casey. The concrete chunk penetrated the car's sunroof. P sued D alleging the Corvette was defectively designed and manufactured and that Ds were negligent in the design, manufacture, and distribution of the automobile. The sunroof was made from a type of plexiglass which was too thin and too weak. He contends there is a relatively inexpensive alternative lexan polycarbonate sheeting which is shatterproof and would have prevented the injury he suffered in this case. D demurred. D claimed its duty did not extend to an unforeseeable intervening act which the manufacturer and seller of the vehicle had no duty to guard against. The court granted the motion. P appealed.