I believe that PRT will be what cities will be using in the future. The "future" being 50-100 years. If you look at the numbers (cost per mile, capital costs, etc.), it just makes far too much sense. The reason PRT hasn't been done is that PRT hasn't been done: the transportation industry is incredibly conservative and awash with monied interests (at least in the US). All it will take is one success, and it should take off.
Look at it this way. If an average city put in a single PRT loop through the middle part of the city, and maybe a run out to an airport, do you think a shopping maul might be willing to through a few million to be added to the loop? How about an apartment complex? It scales the same way the Internet did.
Now, jumping to python here, if we want to help make this happen, the way to do it is to create a simulator where all someone has to do is put in a 3d view of a city and a track pattern, and then they should be able to virtually ride the new system. Multiple CPUs may be required :-). I seem to recall that google was doing a 3d capture of San Francisco a while back. I'm not sure how far that's gotten.
Someone actually made a graphical PRT simulator (maybe two?) in Python. But damned if I can find them. One was of a single station, and one was of a complete network (if I remember correctly). There's one listed here, but it's not the one I was thinking of.
There's work underway on a PRT system for Heathrow airport, and one in planning for Dubai. Hopefully those will work out well. At one point there was work on one for Chicago (O'Hare?), but the project didn't go well. My understanding is that the relationship between Raytheon and Taxi 2000 didn't go very well. Raytheon was looking to move out of defense (peace surplus, hah, remember those days?), and they were foisting decisions on Taxi 2000 (the PRT company that is now SkyWeb) that made the system bigger and un-PRT-like.# Ian Bicking