Better quality raises average age of cars on U.S. roads to 11.5 years. The average age of cars on U.S. roads is at a record 11.5 years, according to research firm IHS Automotive. The average age of cars on U.S. roads is at a record 11.5 years, according to research firm IHS Automotive. Automakers say they are building the best cars ever, and there’s proof on the road. The average age of vehicles in the U.S. has climbed to a record 11.5 years, according to research firm IHS Automotive. The age continues to creep up even though new car sales are at near record levels.