St Louis proper is out. It's a mixed bag in St. Louis County and West County. The problem is that you can literally be fine on one side of the street, and break the law on the other. And, the boundaries are usually not marked. To me, it's just not worth the trouble. Maybe some of the locals can come and tell you more specifically, but keep in mind I'd guess there are 40 or so political subdivisions in that area, and the ordinances are constantly changing.