automakers car benefits car dealership car options car owner car toyota consumers ecosystem efficiency electrical motor electric cars extra care fuel consumption fuel economy gasoline powered internal combustion gas prices generation version green car harmful emissions hevs hybrid car hybrid cars hybrid electric car hybrid electric cars hybrid electric vehicle hybrid electric vehicles hybrid vehicles internal combustion engine launch lithium ion battery modes partial solution periods petroleum plug in hybrids power train price of oil prius second generation tailpipe emissions term basis toil toyota prius traffic what this means