Never is the Law of Unintended Consequences on such stark display as when the government tries to “fix” something.Now, one can argue that the U.S. Constitution does allow for the federal government to build and maintain interstate highways. As such, one can argue that assessing a fee on each gallon of gas purchased in order to fund the construction and maintenance of federal interstate highways is appropriate. A dedicated tax to fund a specific government program targeted at those who use roads, streets and bridges. And that arguably constitutional tax-and-build system has worked fairly well for many decades now. However, Congress just can’t restrain itself to its constitutionally permissible functions. So in 1975 it decided that car manufacturers had to be forced to increase the average miles per gallon every car built and sold in America got. It’s called the CAFE standard.Well, with a gun to its head, auto manufacturers did just that by replacing large, comparatively safe “gas guzzlers” with brand spanking new death traps that were smaller and lighter. But hey, 42 MPG on the highway, baby! Wheeeee!Enter the Law of Unintended Consequences.As Americans buy fewer and fewer gallons of gas, the fund to build and maintain highways and bridges is dwindling, even as the expense for building and maintaining those highways and bridges keeps going up. Add to this problem your typical government mission creep, as funds originally dedicated to building roads and bridges are now being diverted to landscaping, bike paths, sound walls and all manner of other projects other than laying asphalt.So as the federally-imposed CAFE standard continues to go up and the money in the highway trust fund continues to go down, roads and bridges that need to be built and fixed aren’t. What to do?Well, there’s certainly no appetite to increase the gas tax. Nor is there any appetite to “index” the gas tax so that it goes up automatically with inflation. And there’s certainly no appetite to convert what are presently “free” highways and bridges to toll roads.So some are suggesting it’s time to stop assessing highway taxes on gallons of gas and instead assess the tax on the number of miles traveled. To do that, however, would require that every car in American be outfitted with a tracking device controlled by the government — a frightening Big Brother notion that even a populace which has largely accepted traffic cameras at every intersection isn’t prepared to swallow.Frankly, I don’t know what the answer is to this new government-created problem. What I do know, however, is that, unaddressed, the problem is only going to get worse. So perhaps it’s time to move this issue a little higher up on our public policy discussion agenda. • Chuck Muth is president of CitizenOutreach.com.