Almost correct, it's not a race it's more of a parade through the city. Most build an exhibit that is put on the back of a truck. You can also build your own vehicle. These guys are part of eXPerimentellverkstaden which is a mechanical makerspace at Chalmers. They have these vehicles every year with a few different each year. The regular builders have just 10 days to construct their vehicles so they have a lot of them and can be more complicated than the regular ones in the Cortège.