The cost of steel has increased considerably since 1993. So have the cost of concrete, asphalt and other materials used in highway repair, and of the labor that it takes to resurface a road or reinforce a bridge. The sheer miles of pavement and number of bridges have increased, too.

What hasn’t changed in that time, however, is the mechanism that pays for all that maintenance. The federal gas tax, stuck at 18.4 cents per gallon on gasoline and 24.4 cents on diesel, has lost 40 percent of its value in the last two decades to inflation and greater fuel efficiency. The result has been a chronic underfunding of transportation projects, mitigated only slightly by the weak stop-gap measures enacted regularly by Congress.

The latest temporary fix – $10.9 billion transferred to the Federal Highway Trust Fund by lawmakers last year – runs out in May. Congress must use the time until then to formulate a long-term solution that adequately addresses the needs of the country’s transportation infrastructure.

GAS TAX BEST CHOICE

The best and most obvious choice is raising the gas tax, ostensibly a user fee whose individual burden increases the more someone drives. It has been a reliable, if shrinking, source of funding, accounting for a third of the total state budget for road maintenance.

But the political reluctance to raising the gas tax has left a perpetual hole in the highway trust fund. Maine’s portion of the fund dropped by 5 percent in the five years ending in 2013, a real loss of more than $26 million.

And Congress was able to reach that level of funding only by transferring money from general revenue – a total of $65 billion since 2008, which is simply not enough for the projects at hand. The $10.9 billion transferred just before the summer congressional break last year, for instance, did not cover the shortfall of about $16 billion; it just put off the full reckoning.

There is a real impact in Maine. The state transportation department will spend more than $2 billion over the next three years, but an additional $119 million is necessary to bring Maine’s most-used roads and bridges up to minimum standards.

The same is true nationally. According to the American Society for Civil Engineers overview, annual transportation infrastructure spending by local, state and federal authorities has to increase by 11 percent to prevent further declines in condition, and almost double if roads, bridges and transit systems are to improve.

As it is, the United States has dropped from first in terms of transportation infrastructure to 16th. According to AAA, poor road conditions cost the average motorist $300-$500 in annual repairs.

A RANGE OF OPTIONS

To counteract that, Ray LaHood, a former U.S. transportation secretary and Republican member of Congress, is calling for the gas tax to be increased 10 cents and indexed to inflation. The nonpartisan Congressional Budget Office said it would take an increase of 10 to 15 cents to meet current obligations.

Other options are on the table. One idea gaining steam – among politicians as disparate as President Obama and Republican Sen. Rand Paul – is a tax on offshore profits made by U.S. corporations.

Taxes on the wholesale price of gas, or simply on a per-mile basis, has been floated, as have new tolls or the use of private investors.

Each plan has its positives, but also drawbacks, as would raising the state gas tax, which would raise the burden on Maine residents and businesses and put the state at a competitive disadvantage.

Indeed, an increase in the gas tax, with indexing to inflation and perhaps a form of tax relief to low-income drivers, remains the most simple way to fund transportation projects. Congress should end its yearly game of chicken, and its practice of stealing revenue from other sources, and make sure the highway fund is properly funded for the foreseeable future.