Generally speaking; no. At least where I live, it's not even legal if over 12. That said, I do it all the time on a couple sections of unavoidable busy highway near my place. This road is very busy, fast, and lacks a shoulder or bike lane. I've never seen a pedestrian on these, so I'm not endangering anyone. If they really wanted to give me a ticket, I suppose they could. I'd take that over being hit any day. Other than that short section of road, never - I just avoid dangerous roads where possible.