Think you have what it takes to design a hydrogen-powered car? How about the guts to drive one? You can find out now that the Hyrban Project's  Riversimple Urban Car, an open-source vehicle, has been unveiled in London. The British-designed Riversimple, funded by the grandson of Ferdinand Porsche, has a smaller fuel cell than current hydrogen-powered prototypes. That means it needs less hydrogen on-board and in fueling stations.
The Smart Car-sized vehicle travels up to 50 mph and has a range of 200 miles. A six-kilowatt fuel cell from Horizon Fuel Cell Technologies powers the car, which contains a bank of ultracapacitors to store electricity and provide accelerating power. Four electric motors on each wheel double as brakes and electricity generators.
Don't like the design? Feel free to change it on the Hyrban wiki, which contains all the car's juicy engineering details. Anyone can lease the design for free, tweak it to fit local environments, and manufacture it. If Riversimple likes the tweaks, it will incorporate them into its overall design.
Next up for Riversimple: raising the funds to build 10 production prototypes for testing. The original Riversimple car will be available for a 20-year lease when the first fleet is released in 2011 in an as yet-undetermined U.K. city. Fuel costs and access to a dedicated hydrogen fill station set up in Oxford, Peterborough or Worcester will be included in the approximately $330 per month price, with a full roll-out for the car expected in 2013.
Open-source car designing is a valid method for improving alternative energy use in vehicles, but it's unlikely that the Hyrban project's cars will ever make it to the mainstream. Hydrogen cars have been shown time  and time  again to be inferior to plug-in hybrid electric and pure electric vehicles, which is all the more reason for innovative companies to start open-sourcing their electric cars.