Back before seat belts and air bags...  Before fuel economy standards...  Before front and rear impact standards...  Even before they had to have doors...  Anyone could build a motorized vehicle and market it as a car.  The King Midget was one such venture.
The King Midget was a minimalist car, at best.  Although their owners might not agree, the King Midget architecture is pretty much the same as today's street-legal golf carts, right down to the lawn-mower engine used for propulsion.  There were many variations, and customizations, and home-built bodies through the years, but factory cars comprised three 'generations.'
Homepage for The International King Midget Car Club Inc.
Article from the howstuffworks website.