Shared space is a type of roadway that is common in Europe, found in a few places in the United States, and so far as I know, only one place in Sacramento. The concept is that pedestrians, bicyclist, and motor vehicles can mix without having to have set-aside areas defined by curbs and painted bike lanes.
In Sacramento, Liestal Row, an alley between L Street and Capitol Avenue, and 17th Street and 18th Street, is the example. The alley was reconstructed with sidewalk areas defined by smooth concrete and roadway areas defined by bricks, however, there are no curbs in between and no limitations that keep the modes separate. The two businesses in the alley, Edible Pedal and Old Soul, spill out into the alley, and people often stand around in conversation. Often vehicles (including bicycles) have to thread their way between other users. What makes the alley work is that motor vehicle drivers are moving at a very slow speed, and do not have priority over other users. I’ve seen the uncertainty in the eyes of drivers negotiating the space, and that is exactly what makes it safe for everyone, the uncertainty that leads to paying attention instead of making assumptions or driving distracted.