In Orange County, California there is a small city called Lake Forest, like 70% of which is a giant retirement home complex called Leisure World and another maybe 10% is a golf course.  the retirement complex allows golf carts on its roads and there are a couple roads between there, a couple churches, a couple local supermarkets, and the golf course that have dedicated gold cart lanes paralleling the road and sidewalk,with solid dividers betwixt the three, but it is just that immediate city center, so not nearly so impressive a network.