Less than a decade ago, oil cost less than $30 a barrel and drivers pumped $1.50-a-gallon gasoline into their vehicles.

While those good old days aren’t likely to return, several notable events in 2011 showed it’s time for Americans to change at least some of their old ways of thinking about oil. That was then: Any threats to petroleum supplies from the Middle East will result in immediately soaring prices. This is now: From the civil war in Libya to unrest in Egypt and Syria to last week’s warning from Iran that it would close down the Strait of Hormuz, 2011 brought a number of events that could have spiked the cost of crude.

Yet even while oil did briefly close above $110 a barrel earlier in the year, it also dipped months later to around $75 before finishing the year at $100 a barrel. That’s far from the record $140-plus in 2008. And U.S. gasoline prices that soared close to $4 a gallon in early 2011 had plummeted to just over $3 a gallon by late December.

A big part of the reason for the relative stability: Demand remained tamped down in America and Europe because of their continued economic problems. In addition, the more stable Middle East countries such as Saudi Arabia insisted on pumping out enough oil to meet demand in efforts to pay for their own domestic spending programs.

That was then: U.S. automakers will fiercely resist government-mandated programs to boost fuel efficiency. This is now: In mid-2011, President Barack Obama announced a stunning deal with auto companies to essentially double the average fuel economy standard for domestically produced vehicles to 54.5 miles a gallon by 2025.

The administration effectively used some public relations pressure to help its cause, pointing out that taxpayers had helped bail out GM and Chrysler during their financially turbulent times a few years ago. Plus, some domestic and foreign carmakers have been turning out vehicles that get better gas mileage in recent years, showing that decades of “we can’t do this” excuses had been overstated.

The eventual production of tens of millions of more efficient cars and sport utility vehicles will save billions of gallons of fuel while reducing harmful air emissions.

That was then: American automobile companies are shrinking dinosaurs. This is now: The big news locally was Ford’s welcome announcement of a $1.1 billion expansion of its Claycomo automotive plant and the eventual addition of 1,600 jobs. Ford also is adding an additional 5,000 or so jobs and $15 billion in added investment elsewhere.

GM said it would hire several thousand entry-level workers around the country while investing $2.5 billion in factory improvements.

It’s true these companies and Chrysler, the other Big Three member, are smaller than they once were and selling fewer vehicles than they once did in the United States, again largely a result of the lousy economy. Yet it’s encouraging at the start of 2012 to see some positive news about oil supplies, gasoline prices and the improved fortunes of U.S. auto companies.