A lot of states now are amending their motorcycle codes to allow trikes that are by nature not what "we" call a trike.
Slingshots, Morgan M3W and Vanderhall are three wheelers, not necessarily trikes.
But by most state's definitions, anything with three wheels is a trike or motorcycle.
Texas and a couple upper northeastern states had a definition for a motorcycle trike that you had to have handlebars and a seat that you straddle. Of course the three three wheelers I mentioned above do not fit this classification and Texas was not letting the early Slingshots register.
MO as an example had the very basic code that ANYTHING with three wheels is a motorcycle and had to conform to rider's safety standards, "M" endorsement and helmet.
A little over a year ago MO passed a new vehicle code called Cyclecars. These would have three wheels, but automotive type driver controls, single or side by side seating, steering wheel, pedals etc. With this new code you DO NOT have to have an "M" endorsement on your driver's license, but you still have to wear a helmet.
Makes no sense to me about the helmet though. A Miata would be just an dangerous in my mind about a rollover. But does wearing a helmet in a Cyclecar really make you any safer? Who knows, but to DRIVE a Cyclecar you do not need to have motorcycle training.
With the Eleo still being pushed as an economic three wheel car with roof and door etc, they've hit the state legislatures across the country to get this Cyclecar legislation passed to anyone can buy their three wheel front wheel drive car without anything more than their normal auto driver's license.
I've seen several videos on the Vanderhall and still cannot say I'm a big fan of the looks. But the technology is pretty good, also in the Polaris Slingshot.