From the patent photos we have seen it doesn't look like the Slingshot will have a cage over the driver and passenger. So the question is, will you wear a helmet or not?
Not necessarily. See Oregon Revised Statute 814.290. It provides an exemption from the helmet requirement if you are within an "enclosed cab". "Enclosed cab" is undefined in oregon law and there are no NHTSA specifications on what defines enclosed cab either. Since you would sit "in" and not "on" the Slingshot, an argument could be made that you would be exempt. It could be considered a cab, though "enclosed" .... well, that's thin. It would be up to the discretion of individual police officers and subsequently the courts if you were issued a citation. If I do end up purchasing a Slingshot, I do intend to test my theory and my argument.It is mandatory in Oregon, but it will come off as soon as I cross the Idaho border.....
The only protection a helmet is going to provide is from flying debris. If you roll a Slingshot and the hoops fail, you are likely dead.... with or without a helmet. Personally, I think wearing a helmet in one of these defeats much of the purpose of the vehicle. If part of the fun is the open air feeling, the helmet is just going to detract from that. Would be better to have a low slung open top sports car if the open air vibe is what you are after. An open face helmet returns the "open air" feeling for the most part but then exposes you to the greatest risk once again: debris. I'd much rather have a taller rigid-framed polycarbonate windshield and ditch the helmet. ...