Although Pacific Avenue through downtown Santa Cruz, California isn’t designed as a shared space, I think it kind of acts like one on busy weekends when pedestrian traffic dominates. Most of those driving — even tourists with out-of-state license plates — take care to watch for people meandering into the street from arbitrary locations.
This kind of slow traffic naturally improves safety for people on bikes. I’ve talked to people who strongly dislike riding with traffic, but feel perfectly fine biking through downtown.
Even people on horseback are occasionally seen riding through downtown Santa Cruz.
I’m not smart enough to know if it’s culture, design, or what that influences people to drive more carefully here. My crazy hypothesis: we have several people with a tolerance for high risk behavior who are willing to violate social norms and jump into traffic willy nilly.
I can’t recommend this as public policy — even in Santa Cruz, such individuals who dash across busy intersections against a red light are hit by cars — but I think we have a critical mass of people like this who embolden others to claim and own our public spaces.