HARRISBURG — A Democratic plan to raise hundreds of millions of dollars for bridges, highways and mass transit, largely by adding tolls to Interstate 80, passed the House on Wednesday.

The measure was approved without additional debate and sent to the Senate after a 105-96 vote, with five Republicans and all but one Democrat in favor.

Sponsors have said the tolling will be designed to eliminate or minimize tolls for local drivers, although the bill does not detail how that would work. Any such plan, however, is likely to be challenged as unconstitutional.

Duquesne Law School professor Bruce Antkowiak said favoring in-state drivers could potentially violate interstate commerce protections in the U.S. Constitution.

"The general law is you have to be evenhanded, you cannot be just pursuing protectionism of your state," Antkowiak said. "You have to balance the effect that you're having on commerce, interstate commerce, against whatever legitimate state interest you're claiming you're pursuing."

Backers say the bill should generate about $720 million in new highway, bridge and transit funding next year, rising to $1.05 billion by 2016-17.

Chuck Ardo, a spokesman for Democratic Gov. Ed Rendell, said the transit bill was "an important step forward, but still falls short of the billion dollar threshold that he has insisted upon from the beginning."

The bill would require more money from counties and municipalities in order to collect a larger state transit subsidy, and give local governments choices about which new taxes to impose in order to generate it.

The legislation also authorizes a study of tolling Interstate 95 and changes the composition of the turnpike commission and Southeastern Pennsylvania Transportation Authority board.

The House's approval of the transportation and transit bill came three days before Saturday's state budget deadline, but a spokesman for Senate Majority Leader Dominic Pileggi, R-Delaware, said the bill and budget should not be linked.

"The House-passed plan took some major steps forward by eliminating the governor's oil tax and turnpike lease proposals," said Erik Arneson, Pileggi's communications director. "One piece we will focus especially hard on is the ratio of road funding to transit funding."