Definitely not a “mini” car; this is a one-person micro. I didn’t spot any model tags or logos, so it might be a person’s invention or modified golf cart or something, but the body work production values looked too sharp to be anything but a production vehicle. All the dimensions were micro: it was considerably shorter, narrower, and somewhat lower than most cars – even most mini cars.
The front was the one-wheel side, and tapered to a well-rounded, yet sharp-looking point over that wheel (this would be the bridge of the “nose”). The driver’s cab looked like a glass or plastic bubble, riding relatively high and in the middle/back end of the car, positioned in front of the back wheels. It looked like the cab configuration was such that it was possible that he was sitting with his legs extended in front of him, although he could’ve been sitting on a more conventional car seat. The whole vehicle was very curvy, including the rear body over the two wheels in the back (the “nostrils” end). The car was a bright, almost neon lime green (almost chartreuse). I didn’t see, in my fleeting glimpse of it, any obvious storage capacity, although there might have been room in the back for a couple of bags of groceries… maybe.
Since I saw it going the other way on a 30-mile-per-hour street near Westfield, NJ, I can’t vouch for its ability to handle highway speeds.
I’ve already done some Googling, including sites devoted to three-wheeled vehicles, without spotting it (more evidence that it might’ve been a prototype or an individual’s home project). Any ideas or links would be welcome, though…