More Efficient Fuel/Electic Car

I know that they have cars that run on both electricity and fuel, but what if they built an electric car that went more than 100 miles on a charge and then whenever you do run out of electricity, then are able so switch to a gas tank. I think that the biggest improvement would be the more miles per charge that the car gets. I know that the reason why I don't have one is becaus I live so far out of town, coming to Phoenix and back, even with no traffic or any additional stops, I would be very very lucky to make it back home without calling AAA. I also don't have one because there are many people that have no means of charging this car, therefore rendering it useless. I know that this as meant to be more of an in town car talon a toadtrip car, but honestly think that engineers should be trying to target "green" cars for people who commute daily or just live out in the middle of nowhere. With that being said, I think you would get more people wanting to go green if they werent so limited.