Wow,
So many cleaver people who don't live in the US have such insight into the US.
I suppose that would be just as we researched as if I said Europeans are snobs because I [sarcasm]know [/sarcasm] it to be true
The US "officially" adopted the metric system well over a century ago. The issue is converting EVERYTHING over. As our friends in England I'm sure can tell you it's isn't always easy. However, all of my work is don't in the metric system. When I worked in combustion engineering that wasn't as easy because units of entropy don't always convert well.
Personally, I think switching over is a good idea but much like England, I think switching things like miles to kilometers is not that important but actually would cost quite a bit. Half the street signs in the US would have to be changed. ALL of our interstate exits (numbered based on mile marker) would have to change. That’s a BIG impact for what is honestly not a big problem. I mean aside from the fact that it gives Europe something to be snooty about.
As for mpg vs L/100km, well distance per unit consumed is a more typical definition of efficiency but L/100km has some benefits. I don't like that it's not a unit to unit measurement. The 100 part seems improper and rather... like a British unit of measurement. The advantage to the fuel used per distance method is it really shows the difference between say 10 and 12 mpg (20%) as a big deal while the distance per fuel consumed shows it to be just two extra miles. While 40 to 44 mpg looks like a more impressive 4 miles extra it's only a 10% improvement.
PS: Euro snobbery is no more attractive or warranted than American snobbery. Both are distasteful and really not worthy of what is a well run forum.