60mpg (us) is 72mpg (uk), or 4l/100km. A Vauxhall Corsa may claim that[0], but I've got one at the moment as a rental and don't get anywhere near that, more like 45-50mpg (uk) - so about 40mpg (us).
That's 56mpg (American gallons are smaller). It's also a claimed number, real numbers tend to be about 70% of that, which would make it about 40mpg (US).