Another addresses reducing fuel requirements by using extra light-weight composite material for the car's bodies that is stronger than steel but as light as cardboard. Lighter weight means less fuel needed. They need to figure out a way to lower the cars' center of gravity and play with the aerodynamics to keep them from going airborne but that's all being worked on in the lab.
I'm personally excited that we live in an age where we get to see all these new technologies be developed. People alive 150 years ago couldn't have imagined the things we think of as routine. Instant global communications, transportation, refrigeration and indoor climate control, aviation, space technologies and off of the spin-offs, microwave cooking, digital entertainment media from DVD motion picture technology to digital music archiving to entire libraries featuring thousands of volumes that can carry anywhere and hold in your hand over a Nook, Kindle or iPad. Its amazing to me that so many people actively resist technological advancement, especially one that will save lives by bankrupting terrorism.