Obviously, far fewer crashes means fewer fatalities and fewer traffic jams, but it also could mean a big change in car design and fuel consumption. Some companies have created small, two-seat driverless vehicles designed only for city streets. As originally pointed out by climate and energy scientist Amory Lovins, only about one percent of the energy in a gallon of gasoline goes to moving the driver forward. About 75 percent of the energy leaves the tailpipe as heat and almost all the rest is needed to move a 4,000-pound car. But the bulk of that 4,000 pounds is only there to keep the driver and passengers safe in the relatively unlikely event of a major crash. If that risk was reduced dramatically, 4,000 pounds might come down closer to 750 to 1,000 pounds.