I've found a lot of great information about the fuel efficiency of new cars - vial fueleconomy.gov, automobile data sites, and even car magazines, but they all seem to be working with new cars. Are there datasets available for used cars? Does a 5 year old Ford F-150 have nearly the fuel efficiency of a new one? Does a Camry with 100k miles on it match the efficiency of the same car with 100 miles on it?
I realize that there are variables that would skew this (tires changed over the years, if a car was used in a cold or warm climate, if the truck was used for towing or just going to work, etc.) but there has to be some real-life testing being done, right?
This would be just as true of electric cars - batteries will wear out, bearings will get worn down, etc.
Would love to be pointed to some data if you know about it.