Create a vehicle that is capable of running off of human waste.

I know it sounds slightly silly, but if we could harbor the energy that is still located inside of fecal matter, especially human fecal matter, then multiple problems could be solved. Less waste would be dumped in rivers or other water ecosystems, which is becoming a severe problem, and it would be another alternative to the use of fossil fuels until hydrogen engines have been completed. I'm sure such technologies can be easily tapped into.