It just keeps getting worse.

Friday’s stunning surge in the price of oil – more than $10 per barrel – is sure to have an almost instantaneous effect on the price at the gas pump. It will be felt most keenly by those driving big SUVs – which are starting to look like relics from the bygone era of cheap fuel.

Big gas guzzlers have long been demonized by environmentalists and those who view them as ostentatious symbols of American excess. Now they’re causing real fiscal pain to their owners, who are shelling out wallet-busting amounts to gas up their SUVs, “light trucks” and Hummers.

The price at the pump is bad enough, but the real shock may not arrive until owners of gas guzzlers try to trade them in for something more fuel efficient. Close to 40 percent of SUV and truck owners are finding that they’re “upside down” – they owe more on their low-mpg vehicle than it’s worth.

Even so, there’s been a rush to shed the guzzlers and get into smaller vehicles ranging from scooters and small four-cylinder cars to gas-sipping hybrids like Toyota’s hot-selling Prius. When gas prices broke the $4 per gallon mark – and then continued to rise on an almost daily basis – a tipping point seemed to have been reached.

For many Americans, that was the point at which they saw the shape of things to come – and it scared them. Simple economics, not environmental preaching, is convincing many that smaller cars or turning to mass transit to get to work makes more sense. Pierce Transit, for example, reports that weekday boardings are up 10 percent over last year.

The car owners in the toughest crunch are those who choose to live far from their jobs, accepting a long commute for the opportunity to buy a cheaper home on a bigger lot – their own version of the American Dream. That dream now comes at a much higher cost.

Will having to pay so much more for fuel – which is driving up costs throughout the economy – inspire Americans to reduce their living-large habits? Instead of buying the latest hot toy, the bigger TV and the $4 espresso drink every morning – and charging it if they don’t have the cash – will they start living within their means, staying home more and spending less on nonessentials? That wouldn’t be entirely a bad thing.

The fear that the tipping point has arrived has Wall Street in a sour mood – and contributed to Friday’s precipitous decline in stock prices. Americans’ new spending habits have already socked the nation’s automakers, with GM announcing last week that it will shut down four plants producing SUVs and pickups due to collapsing sales. GM and other automakers say they will focus on smaller cars and new technologies. GM may have a 40 mpg car on the market next year and hopes to offer a plug-in hybrid in 2010.

If Detroit had gotten an earlier start on fuel efficiency, we wouldn’t be in such dire straits today – and thousands of autoworkers wouldn’t be jobless. But thanks to cheap gas, Americans have been free to indulge in the notion that “bigger is better” – and automakers had little incentive to change their ways. Meanwhile, Toyota and Honda are riding high with their more fuel-efficient vehicles.

The era of cheap gas is likely gone forever. The demise of the SUV won’t be the only change that soaring oil prices portend for the American way of life.