As political philosophy, “we’ll cross that bridge when we come to it” leads to kick-the-can government. When passive politicians postpone critical decisions, problems fester, sometimes with deadly consequences. Since the I-35W bridge dropped into the Mississippi River in Minneapolis, the saying has a new, literal meaning. Now, when we reach the bridge, we think twice about crossing.

We’ve rediscovered the lamentable condition of the national transportation system. Currently, bridges have the spotlight. In Congress, the folks who always call for higher taxes push for a nickel gas tax hike to fix them. The White House demands smarter spending. And so the D.C. debate reprises refrains familiar in Olympia.

I’d bet against a federal gas tax hike. It looks more opportunistic than heroic. Congress has made the transportation budget a rolling pork trough. Promises to spend the next nickel smarter are not persuasive.

Jerry Taylor and Peter Van Doren, senior fellows at the Cato Institute, a libertarian think tank in D.C., argue that it’s time to abolish state and federal gas taxes, not increase them. When used for construction and maintenance, they say, gas taxes “overcharge motorists in low-maintenance, low-construction locations and undercharge those in high-maintenance, high-growth areas. When addressing pollution … they overcharge rural motorists and undercharge many urban motorists. When addressing congestion, they overcharge non-peak road users and undercharge peak road use.”

They contend, convincingly, that the gas tax is a clumsy, “second-best remedy” to an array of environmental and transportation problems that would be better addressed by specific pollution taxes and road-use fees.

Taylor told me he “doesn’t see any need for the state gas tax,” but finds it preferable to the federal one. Still, he acknowledges there’s “zero chance” politicians will soon cut fuel taxes.

Practical politics aside, however, Taylor and Van Doren are on the right track. Over time, the gas tax will fade dramatically in importance. It’s best now to begin planning for its demise.

Robert Poole, director of transportation studies for the free-market Reason Foundation, is one of the nation’s leading transportation authorities.

A strong advocate of user fees, Poole says, “The gas tax does not seem like a good long-term bet.” Increased fuel efficiency and a possible change in how we power cars and trucks hasten its decline. “But definitely it’s the mainstay for the next 15 years.”

That’s how long it’s going to take to develop viable alternatives. For example, while the technology for tracking vehicle miles traveled – perhaps the best way to tax road use – exists, it’s not widely installed. Poole says for such a system to work, “the feds will have to mandate a GPS box for all new vehicles.” And then give it 15-20 years before everyone has one. (I worry about privacy considerations, but those of us who carry cell phones have probably already lost that battle.)

Meanwhile, we’ll be relying on the gas tax.

“There really isn’t anything that can generate that kind of revenue capacity,” he tells me. But it’s not enough.

Poole favors “limited access” projects that add road capacity for a fee. He cites Georgia, Texas, Virginia, and Florida as examples of states that have pioneered successful programs with the private sector financing, operating, and building toll roads. Because of outmoded formulas for distributing federal highway dollars, these rapidly growing states usually send more money to D.C. than they get back. So they’ve taken the initiative.

In addition, Poole condemns “the uncontrollable growth of earmarks, which fund low priority projects at the expense of the high priority projects that states would prefer to fund.” The combination short-changes essential projects in favor of bridges to nowhere.

Despite steep increases in the state gas tax, our transportation system requires substantial new capital. Spokane’s north-south corridor, Seattle’s Alaskan Way Viaduct, a new 520 bridge: All remain underfunded. Having reached the point of diminishing returns with the gas tax, we’re going to have to accept a transportation future that relies heavily on user fees, tracking devices, restricted lanes and private sector investment – whatever it takes to get the job done.

Before we can cross the bridge to improved safety and mobility, we’ll need to build it ourselves. And pay the toll.

Richard S. Davis, vice president-communications of the Association of Washington Business, writes every other Wednesday. His columns do not necessarily reflect the views of AWB. Write Davis at richardd@awb.org or Association of Washington Business, P.O. Box 658, 1414 Cherry Street SE, Olympia, WA 98507-0658.