A lot further than self driving cars with PRT in fact. 3D rail routing, factory pallet->shop direct delivery, 300mph point to point access, easy emergency and

A lot further than self driving cars with PRT in fact. 3D rail routing, factory pallet->shop direct delivery, 300mph point to point access, easy emergency and disabled access, no batteries to manufacture, no real land use issues (just poles in the ground for hanging systems), fast infra build out using prefabricated track, simultaneous electricity, transport, power (solar, on the top of hanging rails) and telecoms build out with the rail infra. Fully decentralised infra once several tracks are interconnected.