>>7496938And here's my attempt. Wanted to make minifig scale muscle car (Dodge Charger) and a random town car.
I estimated minifig height at average human height, then, according to Wikipedia, dimensions of Dodge Charger (1970 model):
Length 207.9 in (5,280 mm) (1970)
Width 76.6 in (1,950 mm) (1970)
Heigh 53.0 in (1,350 mm) (1970)
So in LEGO minifig scale should be:
Length: 16 studs
Width: 6 studs
Height: 4 studs
Of course you can't get a lot of details but at least managed to fit minifig, even if he's not really sitting in it.