San Francisco may be onto something, although it sounds crazy, taxing drivers by how much they drive.

The Bay Area Transportation commission is moving forward with a study that will determine the feasibility of putting GPS monitors in citizens' vehicles, and using those to assess them a tax for every mile they drive.

Could be a penny, doubtful, or a nickel or a dime more likely.

A mileage tax.

The concept is, if you use the roads, you should pay for them. If you don't, you shouldn't so much.

What do you think of that? Kind of makes sense at first blush doesn't it.

But really the people who are using the roads are paying for them for the most part, through the gasoline tax.

And besides everyone relies on the roads, for emergency vehicles to get to you for trucks to transport goods you need.

So the San Francisco plan doesn't make much sense yet.

But what are we going to do when this dream of alternative fuel cars comes to be... electric cars, no gasoline, no gasoline tax, and no money to build roads.

Pay as you drive isn't as far-fetched as it might sound.