[fwmcbumcrumble]

It's not just the EPA fuel economy requirements. Safety requirements mean cars need a lot bigger doors, more crumble zone etc.

[namdnay]

I think it’s mainly because each new mode year has to be “better” than the last. It’s easier to be “better” (more head room, more boot space etc) when you’re bigger.

So individual models grow and then new ones come in below. For example the rav4 used to be Toyotas smallest suv, now there’s the CHR, and even the Yaris Cross