The Senate is poised to pass a bipartisan overhaul of highway and transit programs, increasing pressure on House Republicans to come up with their own bill or accept the Senate plan.

Efforts by House GOP efforts to pass their own bill without concessions to Democrats have fallen apart in recent weeks. The Senate bill, however, has offered a rare display of cooperation between Republicans and Democrats in a bitterly partisan election year even though the measure's sponsors _ California Democrat Barbara Boxer and Oklahoma Republican James Inhofe _ come from opposite political poles. A vote on the measure was expected Wednesday.

"We are hopeful this will become a template for all of us in the Senate and the House to find the sweet spot where we can work together," Boxer said Tuesday during debate on the measure.

The bill would spend $109 billion over less than two years while increasing the flow of highway aid to states by adjusting current spending levels to take into account inflation over the past several years. States would have greater discretion over how to spend the money, but the bill also would create a new set of performance and project eligibility requirements aimed at preventing waste and making sure national goals are met.

A credit assistance program that helps leverage private investment for transportation projects of national and regional significance would be increased tenfold to $1 billion. In the past, the program has been able to generate as much as $30 in private capital for every $1 in aid, Boxer has said.

The measure also would reduce the number of federal transportation programs by roughly two-thirds in an effort to eliminate duplication. Bicycle, pedestrian, safe routes to schools and rails-to-trails programs _ which were targeted by Republicans _ were preserved by a compromise that moves them into a larger congestion-mitigation program where they would have to compete with other programs for money.

Safety measures in the bill would toughen regulation of the long-distance and tour bus industries, including setting deadlines for government requirements that buses have seat belts, improved roof strength, anti-ejection window glazing and rollover crash avoidance systems. The bus industry transports about 750 million passengers a year, roughly the same as the domestic airline industry.

But amendments added to the bill that provide sweeping exemptions from federal commercial driver's licenses, vehicle inspection and other safety requirements for agricultural trucks operating with 150 miles of their farm were strongly criticized by safety advocates. The amendments by Democratic Sens. Jeff Merkley of Oregon and Amy Klobuchar of Minnesota have broad industry support.

One thing the bill doesn't do is resolve how to keep the federal Highway Trust Fund solvent beyond next year. The largest source of money for the fund, which pays for highway and transit programs, is federal fuel taxes: 18.4 cents a gallon for gasoline and 24.4 cents a gallon for diesel. Revenue from those taxes has declined since the economic downturn in 2008 and because the fuel efficiency of cars and trucks is increasing.

The bill would pay for highway programs through a combination of fuel taxes, cuts to other federal programs and tax changes, but also would drain the trust fund. Some senators have criticized provisions that are supposed to pay for transportation programs since they would raise about $10 billion over 10 years, but spend it in the first two years.

The government's authority to raise money through fuel taxes and spend money from the trust fund expires March 31. The fuel taxes raise about $110 million a day for the government.