Recent evidence that automobile use is declining in America and that some Americans are making significant -- and in some cases not readily reversible -- changes in their lives because of escalating gas prices should be worrisome signs for those who love liberty.

No device is more in keeping with the American spirit than the automobile. Privately owned cars and trucks allow us to go where we want, when want. They are freedom machines.

Still, some liberals would like to use government to force Americans out of their cars.

They believe in socialized transportation, not free-market transportation.

In a free-market transportation system, a person purchases his own vehicle with his own money, buys his own gas with his own money and can drive his vehicle anywhere there is a road -- and, if he has the right kind of vehicle, some places where there are no roads.

Admittedly, the roads generally are constructed by government, albeit with funds extracted from the earnings and gasoline purchases of drivers.

In a socialist transportation system, the government takes the taxpayers' money and purchases vehicles -- often buses or trains -- for itself or a government-funded agency. Where and when these vehicles go is determined by the government.

In a free-market transportation system, a person travels solely in the company of people with whom he has freely chosen to travel. In a socialist transportation system, a person may be compelled to travel in the company of people he does not know and who could even be a danger to him.

I have no doubt that most Americans who love the freedom of movement they derive from owning and operating a car or truck have recognized efforts by various levels of government to induce them to stop, or limit, their driving and cajole or compel them to leave the free-market transportation system and submit to the socialist transportation system.

Methods governments can use to do this include placing constraints on parking availability, forbidding taxpayers from using certain lanes of the highway (or even certain highways) unless they agree to carpool or ride a bus, and imposing excessive gas taxes or road tolls and using the excess revenue to subsidize money-losing public transit.

Artificially suppressing the oil supply is the most significant method government is using today to move people from a free market transportation system into a socialized transportation system.

In May, the Department of Interior estimated that U.S. territory contains about 139 billion barrels of undiscovered oil resources, much of it (85.9 billion barrels) off our coasts on the Outer Continental Shelf. Development of most of this oil is either forbidden or effectively prevented by federal laws and regulations.

Also in May, when the Federal Highway Administration released its monthly report on "Traffic Volume Trends," it revealed that Americans had driven 4.3 percent fewer miles in March 2008 than they had in March 2007. This was the fifth month in a row that Americans had driven fewer miles than they had in the same month the previous year.

"The March 2008 data," Federal Highway Administration spokesman Doug Hecox told me, "represent the sharpest single-month drop in vehicle miles of travel in the 66-year history that such data have been collected."

Are we at the beginning of a fundamental shift in the way Americans use cars? The lead article in Tuesday's Washington Post suggested this might be so. It was headlined, "Fuel Prices Challenge Cars' Reign," and relied partly on a survey of 43,000 American drivers released on June 9 by The NPD Group, which does market research for private industries.

The NPD survey showed that some Americans have indeed made changes in their lives because of historically high inflation-adjusted gasoline prices. According to a statement released by the company, 12 percent said they have cancelled a vacation because of the gas prices; 12 percent have carpooled; 8 percent have taken public transportation; 8 percent have vacationed closer to home; 6 percent have purchased a more fuel efficient vehicle, 6 percent have worked from home; 6 percent have worked closer to home; 4 percent have worked less; 3 percent have sold a less-fuel-efficient vehicle; 2 percent have moved closer to where they work; and 1 percent have purchased an electric or hybrid vehicle.

Hopefully, the 8 percent who have taken to socialized transportation represents a trend that can be reversed.

We should drill our own oil -- now. And, when the supply naturally diminishes to where prices drive the market elsewhere, American entrepreneurs must create another fuel whose production the government cannot readily curtail, and that keeps Americans driving where they want to, when they want to, in privately owned cars.