Instead of (or along with) taxing gas which isn't working quite as well as cars become more efficient with gas, why don't we tax homes in relation to how far away you are from city centers? Give tax breaks to the people with the more compact downtown area even. There could of course be some tax forgiveness to homes (farms) that provide food or other supplies to the city. Maybe there could be separate taxes like one for electricity, one for natural gas, so if the homeowner has solar panels and aren't hooked up to the grid then they don't get taxed for it. The reason I believe this is better is because it not only discourages driving (long commutes) but also discourages sprawl and is more fair to the taxpayers since the people closer to the city aren't putting as heavy a burden on the city's resources. Homes farther away require more materials to transport electricity and gas and water. Of course theses funds should be put to use to revitalizing the city centers and making them cleaner, more eco-effective, and a better place for people so people will want to live there (Think free transit, weather arcades or walkways, green rooftops, pedestrian centers or whole pedestrian cities).
I'm sure people in suburbs or out in the woods on their three acres of land wouldn't like this idea but other people should not be paying for their choice of moving father out so they can have their own private piece of nature.