> the trip we're about to take to Gloucester, Mass., for the hols.
> The three of us on Amtrak, about $300 roundtrip, not counting
> getting from Boston to Gloucester. By car, about $50.
Gas isn't the only cost of your trip; AAA estimates about $0.70/mi all-in for an average car. Driving is still cheaper than Amtrak, I grant you, but even in your dream world of gas being double what it is today, you're more than likely to drive anyway: because of the convenience of having your car once you get there.
Gar makes a great point -- that you've dismissed on-list before -- that without commensurate investment in alternatives, just making it expensive won't keep you from doing it. You'll just further stratify the inequality in the US.
> Gas costs less than bottled water. That's insane.
If you want to see insane (poverty), double the price of gas.
/jordan