There aren’t many taxes that are as fair as the gasoline tax. People who put gasoline in their vehicles pay a per-gallon tax that then is used to maintain the highways those people drive on. There’s a direct link between cost and benefit.

The current problem, however, is that the federal gasoline tax hasn’t kept up with the need to maintain and expand the nation’s highways. The tax — 18.4 cents per gallon for gasoline and 24.4 cents for diesel fuel — hasn’t changed in about 20 years. During that time, cars also became more fuel-efficient, meaning that vehicles are using fewer gallons of gas to travel the same number of miles.

That has left the Federal Highway Trust Fund in dire straits. Without an influx of money, the fund could run out of money by August, and yet, Congress has been unable to reach agreement on how to shore up this critical fund.

Various solutions have been proposed. Republican House leaders offered a short-term plan that would transfer to the highway fund money saved by rolling back Saturday postal deliveries. Democrats proposed eliminating tax breaks for U.S. corporations operating overseas. Some members of Congress also are looking at a way to base a tax on actual miles traveled rather than the amount of gasoline consumed to help account for hybrid and electric vehicles.

So far no agreement has been reached, which is a matter of concern to states, like Kansas, that are moving forward on major highway projects that are supposed to be funded largely by federal dollars. For instance, about $140 million of the $186 million cost of the South Lawrence Trafficway is due to be paid by federal funds. The Kansas Department of Transportation said last week it can continue work on projects like the SLT for several months before it runs out of money, but after that, funding gets more uncertain, as do the 175,000 Kansas jobs tied directly or indirectly to the state’s current 10-year transportation program.

Congress can’t seem to agree about much these days, but this problem demands a solution — now. There may be other options, but for now, an increase in the gasoline tax makes sense. The tax is paid by the people who use the highways, and an adequate highway system is vital to America’s system of transportation, commerce and national security.