Why dont we legalise PEV'S

For those who dont know, PEV means personal electric vehicle.

Electric bikes, electric scooters, and electric unicycles are all illegal besides the stupidly underpowered e bikes, and if we are moving to a more green energy consumption, legalising these things can get people out of cars, which reduces traffic and reduces emissions.

Why aren't any states focusing on legalising these things, instead they're outlawing them and treating their riders like criminals.