Street legal I think not. Maybe in Europe, but not in the U.S.
Why do you think Bombardier made a trike and not a quad?
If it has 4 wheels, it must conform to the same requirements as cars.
That means crash tests, air-bags, bumpers, and all the other crap that adds a 1000 lbs to the average car.
With 3-wheels, that makes it a motorcycle according to the Feds.