Between the normal supply/demand cycle that peaks in the summer, and the unrest in the middle east, some experts are predicting that gas will top $5/gallon this summer. (Story HERE.)
Ouch! Expensive gas always has a negative impact on the economy. When people are pouring their money into the gas tank, they're not buying filet mignon and speedboats and junkets to Vegas. Since it's an election year, I expect the incumbents to do everything they can to keep prices down. They don't want their supporters to stay home on account of not being able to afford the trip to the voting booth.
If past history is any indicator, commuter habits seem to be impacted by a run-up in gas prices, more than pretty much anything. Our office bike-parking facility bulges when the weather is nice and gas is expensive.
Naturally, those who will be impacted the most are those who choose to live long distances from their daily destinations. And particularly those who live far away, and who drive Hummers, super-duty pickups, etc., for their daily transportation.