Following the success of the first X-Prize challenge, which saw a budding hopeful build an aircraft that could escape earth’s atmosphere, the philanthropic foundation has now set its focus on the automotive world. The aim this time ‘round is to build and race a commercially viable vehicle capable of meeting set emissions targets and able to achieve at least 100mpg in fuel economy.

Organizers have now released the first set of draft guidelines in an attempt to gather the public's feedback. Some of the rules include the establishment of two separate vehicle classes. One class will be for vehicles that car seat four or more passengers with a minimum of four wheels, while the second class will be for two seater vehicles with no set wheel requirement. Total greenhouse gas emissions must measure no more than 200g/mile, while all pollutants must also be in line with US EPA’s Tier II, bin 5 standards.

Competitors will be in the running for a multi-million dollar cash prize and can get a look at the new draft when it’s publicly released at the New York Auto Show later this week. One of the first major deadlines will be in 2009, where the cars will have to compete in two long distance races and run on fuel provided by the X-Prize founders.