The average weight of a mid-sized sedan is about 1,500kg, and the average weight of all American cars is closer to 1,900kg. A 4-seater close to 1,000kg is exceptionally light by modern standards. The Mazda MX-5 is a 2-seater which is famous for being lightweight, and it also weighs a few kg above a ton.
Also going off maximum human capacity isn't great in context, as the average car journey has <1.5 occupants. Not to mention if this was codified, car manufacturers would simply put folding seats in the trunk.
Also going off maximum human capacity isn't great in context, as the average car journey has <1.5 occupants. Not to mention if this was codified, car manufacturers would simply put folding seats in the trunk.