However, gasoline is limited, especially when you have nowhere to pump it from. There is current development of electric cars such as Nissan Leaf, BMW I3, Tesla's rockstar models and many trucking companies researching for electric alternatives for trucks.
In Jericho, they figure out how to use mechanical voltage regulators (something that is in almost every farm machine, especially tractors).
Solar panels aren't difficult to obtain and a kid in Africa managed to create a windmill from scrap parts.
This proves that electricity is easier to create in its raw form than pumping gasoline pass that in to a generator or a turbine - even a car engine.
Also, the process of creating an electric car is "fairly easy" given time, money, and the correct skills. Still, it is not impossible to create from scavenged parts in the post-apocalyptic world.
Would it be viable assume that electric cars would be the main transportation in the capital wasteland, and not gas-driven cars?