The problem that this is the wrong measure to use emissions per mile, when it's really about emissions per trip. A car flying down the freeway uses less emissi

The problem that this is the wrong measure to use emissions per mile, when it's really about emissions per trip. A car flying down the freeway uses less emissions per mile, but if one is traveling 50 miles versus just walking to down the block the former is using a lot more emissions even if it is more efficient per mile.