Unfortunately, some people don't realize that "Open Source" has a definition. They think it's a loosey-goosey term meaning "stuff that people like", more or less. So they apply it to anything which can be opened, like a door, or a box, or in this case, a car (english). Sorry, no. Unless they're actually publishing the design specifications, the blueprints, the CAD files for this car, it's not an Open Source car. And apparently Hilmar Simoncontacted them and no, they're not planning to give the design away to anybody.