Resources were used to build the vehicle. If a car ends up in the junk yard while still drivable or economically repairable, I wouldn't consider the car to be "

Resources were used to build the vehicle. If a car ends up in the junk yard while still drivable or economically repairable, I wouldn't consider the car to be "fully depreciated". The objective function I'm considering is emissions/deaths per mile. The most extreme example would be a car with a catastrophic failure that will happen at 200k miles, but the owner only drives 1k miles per year. Parts will become an issue far before the useful life of the vehicle is up. The resale value would be basically 0 after 50 years because everything is so out of date, from safety features to creature comforts.