Legislation aimed at filling potholes and fixing bridges is rarely sexy, so the pending "highway bill" isn't grabbing headlines. But with Congress poised this week to pass a temporary measure to fund road, transit and rail programs, it likely will have a greater direct impact on Americans than most congressional initiatives this year.

Competing House and Senate highway bills have passed their respective chambers. But it is expected that the House version, which would pump $10.8 billion into the federal Highway Trust Fund through May, will survive and clear both chambers by Friday, when the fund no longer will have enough money to cover promised aid to states.

Here are four things you should know about the Highway and Transportation Funding Act:

1. It leaves the gas tax alone

The bill calls for the federal gasoline tax to remain at 18.4 cents per gallon, its level since 1993. But that doesn’t mean you won’t pay more at the pump in some states.

Revenue from the tax has dropped in recent years because of increased vehicle fuel efficiency and because Americans are driving less. Compounding the problem are increased highway construction costs and a gas-tax rate that has remained the same since the Clinton administration.

So to help pay for highway projects, a handful of states have raised their gas tax since 2013 (including about eight states this year), with several more considering the move.

Even libertarian-leaning New Hampshire passed a gas tax increase — 4.2 cents per gallon — for the first since 1991. “A modern and solid transportation infrastructure is essential to the success of New Hampshire's people and businesses," said Gov. Maggie Hassan as she signed the bill into law in May.

2. It kicks the can down the road

Since lawmakers haven’t been able to find a politically acceptable, long-term plan to keep the trust fund afloat, they instead have relied on a series of temporary fixes.

But critics complain that’s no way for Congress to deal with the nation’s aging transportation infrastructure, saying it risks road safety and compromises the nation's economy.

“Renewing the debate next year under a new Congress would start us over at square one, making it nearly impossible to secure long-term transportation funding anytime soon,” said AAA auto club President and Chief Executive Bob Darbelnet. "It’s time our leaders in Washington stop the hand-wringing and start taking real steps to shore up funding for the roads and bridges that we rely on every day."

Even lawmakers admit the current stopgap spending bill — intended to buy Congress time to come with a permanent solution — just kicks the problem down the road at a time when a long-term plan is needed.

“This is a serious problem that demands bold solutions, and I believe strongly that Congress must immediately get to work on a long-term plan,” said Sen. Rob Portman, R-Ohio.

3. If the trust fund dries up, then what?

A deficient trust fund would temporary shutter about 100,000 road projects nationwide and put 700,000 construction jobs at risk, according to a collection of more than 60 transportation and construction-industry associations, business groups and other organizations in a July open letter to Congress.

Some states would fare better than others in that scenario.

Analysts predict that Maryland, for example, would be in OK shape, partly because the state raised its gas tax last year. Still, the Baltimore Sun reported this month that Maryland officials have lowered their expectations for federal aid in future years out of concern that lawmakers will be unable to resolve the long-standing debate over how to close the fund's deficit.

States that recently have raised gas taxes haven't collected much revenue yet, leaving most still heavily dependent on federal highway aid.

"Hundreds of thousands of American workers depend on these investments for their livelihoods. Multiyear funding is the only solution to rebuild our crumbling roads and bridges the right way," said James T. Callahan, general president of the International Union of Operating Engineers. "We urge lawmakers to move swiftly and move boldly before the Highway Trust Fund runs dry."

4. Proposed long-term solutions

Congress has kicked around alternatives to prop up the trust fund, though none has gained significant traction.

One proposal is for a mileage-based road tax to supplement or replace the federal gas tax. Proponents say it’s more fair than a gas tax because if you drive more, you pay more.

Rep. Earl Blumenauer, D-Ore., wants to increase the federal gas tax to 33.3 cents a gallon after 2015 but phase it out by 2025, when it would be replaced by a mileage tax.

And House Republicans have suggested replenishing the trust fund with savings from discontinuing Saturday postal service.

Congress could look to the states for inspiration, as Virginia last year eliminated the state's 17.5-cents-per-gallon gas tax but replaced it with a new tax on wholesale gasoline, a sales tax increase and a litany of higher taxes in Northern Virginia.