It has been tried, but it quickly turns into a dystopian hellscape. If you don't have people on the streets they turn into crime dens. Meanwhile, the skywalks a

It has been tried, but it quickly turns into a dystopian hellscape. If you don't have people on the streets they turn into crime dens. Meanwhile, the skywalks are not visible from the buildings so they lack social control - and are completely unreachable for emergency services. Not to mention that the main benefit of pedestrian areas is the wide-open spaces connected to a dense network of local infrastructure, which such a skywalk would not provide. The only way this works is by separating out the cars - like highways are doing. Due to the lack of physical space to exist and the huge speed difference they are completely incompatible with non-car traffic.