I've been an occasional lurker here for a while...been a peak oil/peak everything activist for 15 years, seen all of these alt transport systems over that time, and IMO none of them stack up, including compressed air.
Some seriously important things to consider:
1. we're addicted to an INDUSTRIAL (rip the biosphere apart) "civilised" model, that says 24/7: we MUST have cars, and therefore MUST have roads, and all they entail. Considering how bad The 6th Mass Extinction is, trying to keep this "civilisation" going on compressed air, is not an option to me.
2. We "civilised" are given a lifestyle structure where we are mandated to drive everywhere for everything. Our human settlement patterns are insane: as in pathologically, suicidally disconnected from physical reality.
3. We are living at the end of 'The Age of Exuberance', and deeply believe that 'Cosmeticism' and denial of physical reality will save the day...go read through the definitions page at
http://greatchange.org/footnotes-overshoot.html. Compressed air cars meets my definition of 'Cosmeticism'...
4. The EOREI of oil based cars is pretty good (oil/gas is free, we just pay for extraction/shipping/refining/distribution....pity about Peak Oil eh?), electric cars not very good, maybe compressed air is slightly better, but relies on a huge oil-based INDUSTRIAL system to keep on truckin', REGARDLESS of what fuel you use....it's STILL a car!
5. Maybe as a transition tech moving away from oil powered cars for RELOCALISATION, compressed air micro-cars may have some use, but right now electric assist bicycles are ecologically light years ahead.
As an afterthought, a friend was brainstorming with me about 10 years ago about compressed air. He came up with a creative re-use of old tech being abandoned in New Zealand. When Maui gas was really cheap (and the oil co's were desperate to use it as fast as possible to make more profits up front!), the government got in behind a subsidised vehicle fleet running on LPG and CNG. Now that that era is over, there are hardly any vehicles still running on LPG, and CNG has been abandoned. So take the old large CNG tanks away from gas stations, and park them next to a windmill that can mechanically pump air into them. Maybe get the pressure up enough to fill scuba bottles, to run a converted ICE neighbourhood vehicle or 2, just for essentials...everyone else go local, or on ya bike! Recycling/restoring/repairing/re-using existing INDUSTRIAL technology seems to make more sense than retooling and building new factories to churn out new cars of any sort, IMO.
Disclosure: I ride an electric-assist cargo bike for a lot of my around town Permaculture gardening/design work, and haul my entire kite and juggling stall to and from the local market on it on Saturday mornings. It's the least I can do, and I admit it's only a transition tech, as the authoritarian technics required to build it and keep it going are not sustainable or good for my community. Read what Lewis Mumford has to say about authoritarian vs democratic technics :
http://www.primitivism.com/mumford.htm
