The Virginia Senate passed a nickel gas tax increase on Wednesday that will help generate $4.5 billion for crumbling roads and bridges around the state over the next five years.

But that proposal differs drastically from Gov. Bob McDonnell's House-approved plan to eliminate the gas tax and raise the sales tax to bring in $3 billion for transportation. If lawmakers cannot bridge that gap before the General Assembly session ends in 10 days, they'll leave Richmond once again without solving the roads crisis.

"As long as the [final bill] resembles the Senate plan, we will have a transportation bill this year," said Senate Minority Leader Dick Saslaw, D-Springfield. "If it varies too widely, we likely will not."

The House and Senate have agreed to tax Internet sales at the virtual checkout counter and allocate most of that revenue for transportation, including $300 million for the Silver Line to Washington Dulles International Airport. The online sales tax would raise more than $200 million a year but it requires approval from Congress, which has consistently dismissed similar proposals in recent years.

There is also consensus to raise $550 million over the next five years by increasing vehicle registration fees by $15.

But that's about where the similarities end. The Senate plan, which passed with support from six Republicans and all 20 Democrats, raises the gas tax from 17.5 cents to 22.5 cents per gallon with future increases tied to the cost of road construction. It also slaps a 1 percent sales tax on wholesale gasoline and allows localities to create a penny sales tax to generate money for local road projects.

Some Northern Virginia Republicans in the House are receptive to the local tax hikes, but Del. Dave Albo, R-Springfield, said the current Senate proposal "even for me goes too far."

McDonnell and the Republican-controlled House are pushing to eliminate the gas tax while increasing the sales tax from 5 cents to 5.8 cents. They also want at least $811 million over the next five years to come from the general fund, which pays for education and social services.

Senate Democrats allowed $50 million a year to come from the general fund, but that came reluctantly. House Minority Leader David Toscano, D-Charlottesville, said it's unlikely they'll budge on that.

Those kinds of lines in the sand are already threatening a compromise as representatives from both parties begin to meet behind closed doors to find a solution that can pass both chambers.

"If we're going to start ruling out things almost from the beginning," said House Majority Leader Kirk Cox, R-Colonial Heights, "we're going to have a lot of trouble getting there."