Since I'm both in favor of increased taxation and worried about oil usage, it's tricky for me to always be arguing against the gas tax, but nevertheless:
The gas tax is a user fee. Drive more, pay more. Drive a heavy gas guzzler which creates more road wear, pay more. Drive in congested hours when gas mileage is low, pay more. So the gas tax encourages efficiency and environmentally-friendly. Reduce your driving, drive a smaller car, use public transit, avoid peak hours, and you pay less.
It's not quite so easy. Let's say I never drive. I have an allergy to cars. I live two blocks from my office. But I purchase products. I shop. I work for a company that distributes a good. I'm still benefitting from a national highway infrastructure, and yet I'm not paying a cent. When the subject is roads, "user" isn't quite so easily defined.
What continually concerns me about these proposals is that they treat driving as optional. When you tax, say, alcohol, and argue that the user can avoid it by not being such a lush, you're right. I could drink less beer than I do and pay less in alcohol taxes. Not so with driving. If I live in an urban area with a massive public transportation system (which I do), my decreased auto usage isn't evidence of environmental enlightenment, but circumstantial. When I lived in Orange County, my heavy car usage was the direct result of the spatial realities of suburban Southern California.
Were there a way to separate necessary from unnecessary auto usage, I'd be happy to endorse a luxury driving tax. Nail me when I go on a road trip, or to the movies, or to look at the ocean. But we can't do that. And given that wealthier folks can purchase homes nearer to their work and buy newer cars with better fuel technology, the tax is instantly regressive. Occasionally, various advocates suggest augmenting it with some sort of rebate to the poor, but not only do none of the regressive gas taxes currently support that feature, there's no reason or proof that any future one will. So in this context, I see no evidence that raising the gas tax is a better or fairer way to fund infrastructure development than any number of more broad-based, progressive revenue sources.
