WASHINGTON -- The House and Senate have reached agreement on a five-year, $281 billion transportation bill that would increase spending to address the nation's aging and congested highways and transit systems -- a legislative feat lawmakers and President Barack Obama have struggled throughout his administration to achieve.

The bill, unveiled Tuesday, also would put an end to the cycle of temporary extensions and threatened shutdowns of transportation programs that have bedeviled Congress for the past seven years, making it difficult for states to plan long-term projects.

U.S. Rep. Jason Smith, R-Mo., said he supports legislation that authorizes funding for the nation's highways.

"This bill fully funds all five years, and Missouri stands to get an additional $100 million per year. A lot of those resources will be pushed to our local communities and towns," Smith said, but he warned a better funding approach is needed. "I am glad that this highway bill is fully funded, but we need to find a sustainable, long-term financing option for the much-needed infrastructure upgrades in our country instead of short-term, piecemeal approaches."

Missouri Department of Transportation district engineer Mark Shelton welcomed the congressional agreement.

"A long-term deal allows us to plan things better and make better decisions on road projects," he said.

Cape Girardeau Area Chamber of Commerce president and CEO John Mehner said, "I am excited that we finally have a five-year deal. It's a step in the right direction."

But Shelton and Mehner said they have yet to see the details of the highway bill, and they cautioned the legislation won't resolve all of MoDOT's funding challenges.

Mehner added, "This is not a cure-all."

The 1,300-page measure was "a mammoth task," said Sen. Barbara Boxer, D-Calif., one of the bill's key negotiators.

"I expect this bill to have a huge amount of support throughout the country from businesses and workers alike," she said in a statement. "Although it is not perfect, I believe it is a major accomplishment for our people who expect us to fund a top-notch transportation system."

The bill boosts highway spending by 15 percent and transit spending by 18 percent over its duration.

It also authorizes $10 billion over five years for Amtrak, $12 billion for mass transit and $1 billion for vehicle-safety programs.

That money is subject to annual spending decisions by Congress, however, rather than being paid for from the federal Highway Trust Fund.

The bill still falls far short of the $400 billion over six years Transportation Secretary Anthony Foxx has said is needed to keep traffic congestion from worsening, and it puts off the difficult decision of how to pay for transportation programs sustainably.

The federal 18.4 cents-a-gallon gas tax, the main source of Trust Fund revenue, hasn't been increased since 1993 and no longer covers annual spending on transportation.

The House and Senate still must vote on the final bill.

Passage is expected by Friday, when government authority to process aid payments to states expires.

The bill is paid for through a series of revenue-raising provisions, some of which have been criticized as gimmicks and budgetary sleight of hand.

One of the hallmarks of the bill is the creation of new programs to focus transportation aid on highways regarded as important "freight corridors" in an effort to reduce major bottlenecks and speed the delivery of goods.

Southeast Missourian staff writer Mark Bliss contributed to this story.