Dunno about no go zones, but the bike lane next to my old place was pretty horrendous. It went down a fairly steep slope next to a four lane road, about halfway

Dunno about no go zones, but the bike lane next to my old place was pretty horrendous. It went down a fairly steep slope next to a four lane road, about halfway down the hill the lane cuts across into the middle of the street about 100m up from a 4 way intersection with a highway. You have the cross the highway in the very center of the intersection, between all the cars, then on the other side, the bike lane cuts back across traffic, then vanishes for a block or so before starting again on the sidewalk. The first time I rode my bike down there I terrified. You don't have much time to react, the hill creates a blind spot at the point where you have to cross traffic and because the road is used by people trying to beat traffic during rush hour, drivers speed constantly and don't really pay attention. Just on foot i've almost been hit by cars a few times at the top of the hill. Definitely not my favourite route.