Well, not exactly on the streets, but in designated marijuana smoking lounges.
Marijuana lounges approved by Las Vegas City Council | Las Vegas Local Breaking News, Headlines | fox5vegas.com
Las Vegas City Council passed the ordnance allowing retail marijuana stores and dispensaries to apply for special use permits to open marijuana lounges.

Somehow, I picture them ending up in those transitional, warehouse-y districts of Vegas, not anyplace residentially nice, or anyplace cool.