The U.S. Senate on Wednesday approved a two-year blueprint for transportation that gives states greater spending flexibility, allows the federal government to set minimum safety standards for subway systems and buys time to find a solution for a funding system teetering on the verge of bankruptcy.

The bipartisan bill was approved 17 days before current transportation funding and authority to collect the federal gas tax that support it are due to expire. After efforts to move a House transportation bill stalled last week, the Senate bill might hold the only chance that legislation reaches the White House before the deadline. It won broad support, passing on a vote of 74 to 22.

“On March 31, if we don’t act on this transportation bill, everything will come to a screeching halt,” said Sen. Barbara Boxer (D-Calif.). “We are very close to the day when everything will stop.”

The Senate bill boils down the number of federal transportation programs from about 90 to fewer than 30, gives states money for projects that ease congestion and air pollution, increases highway safety funding, cuts red tape that delays projects, and expands a federal program that provides loans and loan guarantees to encourage private investment.

It also mandates for the first time that federal safety standards be set for transit systems, regulation that has been pressed for by Sen. Barbara A. Mikulski (D-Md.) since the 2009 Metrorail crash in which nine people died.

“We have federal safety standards for planes, trains and automobiles. We need them for transit systems like Washington’s Metro,” Mikulski said. “I will keep pushing forward on reforming Metro until it’s safe for the people who work on it and the people who ride on it.”

Maryland’s other senator, Benjamin L. Cardin (D), played a central role in protecting funding for popular bike and pedestrian programs. Joining with Sen. Thad Cochran (R-Miss.), Cardin crafted a successful amendment that created a competitive grant program for those projects, with the winners to be selected on the city and local level.

Although the massive bill reshapes federal transportation programs and priorities, it does not resolve the most pressing federal transportation issue: how to meet the financial demands of replacing systems nationwide that are reaching the end of their life spans.

The $109 billion Senate bill bridges a funding gap by raising almost $10 billion with several moves that critics have denounced as gimmicks. One would transfer $3.7 billion from a trust fund established to pay for damage caused by leaking underground storage tanks. An additional almost $2.8 billion would be raised by ending a tax credit for paper manufacturers, and hundreds of millions more are projected to roll in by pursuing delinquent taxpayers.

“Recent declines in gas tax collections, and Congress’s desire to spend more than what will be collected, has led them to poach additional sources of revenue,” said Ryan Alexander, president of the nonprofit group Taxpayers for Common Sense. “The Senate bill uses budget gimmicks.”

The funding maneuvers by the Senate allow continued spending slightly above current levels without addressing the central issue that has delayed new long-term transportation funding since the last legislation expired more than two years ago.

The Highway Trust Fund’s primary source of revenue, the 18.4-cent-per-gallon federal gasoline tax, has not kept pace with transportation needs. Without an infusion of new cash, it has been projected to run out of money as early as next year.

Neither Congress nor the White House has shown an appetite for increasing the tax or embracing the foremost alternative, a tolling system that would charge drivers for miles traveled.

The differences over tolls on more highways were made apparent Wednesday by competing amendments, one that would have banned new tolls on existing interstates and another that would have given states the ability to expand the use of tolls. To speed passage of the bill, their sponsors agreed that neither should come to a vote.

“If we want to pass another transportation bill when this one expires in two years, we must address the structural flaws in the highway trust fund,” said Sen. Thomas R. Carper (D-Del.), who sponsored the toll-road amendment. “I hope our respective amendments represent the beginning of an honest and important conversation about our nation’s long-term transportation needs and how we pay for them.”

The House is away this week, but on Wednesday of last week, House Speaker John A. Boehner (R-Ohio) failed in a closed-door meeting to persuade House Republicans to rally around a five-year House bill.

The following day, Boehner didn’t rule out simply waiting to act on the two-year Senate bill.

“As I told the members yesterday, the current plan is to see what the Senate can produce and to bring their bill up,” Boehner said. “And, in the meantime, we are going to continue to have conversations with members about a longer-term approach, which, frankly, most of our members want. But at this point in time, the plan is to bring up the Senate bill or something like it.”

The alternative to final congressional approval would be a short-term extension that keeps funding at current levels. That would be a setback for state governments, eager to have new funding authorization that allows them to set their longer-term project plans.