It is an option, you go into the setup (tap left + right buttons once), go through the different setup items till you get to the "metric" screen, and set it to 1 (if you want metric display)
It will then display labels in their metric versions, i.e. L(iters) instead of G(allons), K(ilometers) instead of M(iles), L(iters per 100)KM instead of MPG, and do all the appropriate conversions.
The setup values are still in "english" so that we don't have to complicate the user contributed
Table of car settings.