At Clarion Hospital:  An un-named 72-year-old Cooksburg area resident was treated for the injuries which he received in a traffic collision, in Northern Clarion County.     The Cooksburg man was driving a truck on Route 66, at the village of Leeper, in Farmington Township.     At the intersection with Route 36, his vehicle failed to stop for a red light at the traffic light controlled intersection.     At the same time, anoher truck, driven by an un-named 74-year-old Leeper area man, was traveling on Route 36, with a green light signal.     State Police say that the Cooksburg man's truck struck the other truck operated by the Leeper area man.     Assisting, at the scene, were Farmington Township fire-rescue and both Farmington and Clarion Hospital ambulance crews.