I had a similar thing happen to me while I was on a trip 2 years ago in my 1991 Integra LS. I was driving at about 40 mph when the car just shut off. It turned out to be the ignitor. I had it replaced at an Acura dealership for under $200. My car had about 120k miles on it at that time. Correct me if I am wrong but since his car died while he was driving it can't be the starter that has gone. Hope this helps.