In this post from Worldchanging by Jeremy Faludi he discusses some of the latest in rapid transit systems, including the proposed Skyweb express in the US:
"Wouldn't it be nice to have a bus waiting for you every time you walked up to a stop? And wouldn't it be nice if the bus just went to your destination, without stopping anywhere else in between? The main reason people drive is for convenience like this. But if public transportation were as cheap as a bus and as convenient as a cab on roads with no traffic, why would anyone bother driving anymore? That's the idea behind "Personal Rapid Transit", an idea that's been around for forty years, but is still struggling to see the light of day.
The basic idea is having an elevated track with personal-sized cars, only big enough for 2 to 4 people (and normally used for solo trips). Cars on the main track always go at full speed, with cars shunting off to side tracks for entry & exit at stations. These stations would be located a reasonably short distance from each other so users would never have to walk too far to get to a stop, and stations would always have empty cars waiting for the next user to arrive. This individualized service would be made possible by having all the vehicles automated--no human drivers in the system, just smart network-management software."