The idea of “shared space” is to denude a street of most of its conventional markings and features and create a different urban landscape in which motorists and pedestrians are put on an equal footing, so to speak. Drivers start to behave in a very different way amid the new uncertainty, moving slowly, making eye contact with pedestrians, and becoming aware of much more than whether the lights have gone red. Or so the theory goes.
I think something like this could potentially work in the US, as long as the street and surrounding environment looks like a pedestrian/slow speed zone. In fact, I believe they have used this concept at the City Circle in downtown Indianapolis. If you happen to be passing through there, you should check it out.