There's a guy here in C'ville that regularly rides one on the street. i've ridden by him a few times (for a few blocks, before I get on my way) and he can average about 15 mph, but says that up hills, it really sucks. He's got a big orange triangle and a tall, orange pennant type flag for increased visibility. I think they're sweet, and would love one for grocery runs, but I'd be concerned with the width factor - I ride down roads that are already almost too narrow, since cars like to blow by you.