By Keith Laing - 03/08/12 03:18 PM EST
The amendments to be considered include a measure from Sen. John HoevenJohn HoevenMajority of GOP senators to attend Trump convention Death threats against senators remained on Twitter for 2 weeks Senate panel approves funding boost for TSA MORE (R-N.D.) that would authorize the Keystone XL pipeline without President Obama's approval, and one from Sen. Ron WydenRon WydenWhy you should care about National Whistleblower AppreciatIon Day Dems push to require presidential nominees to release tax returns Legislators privacy fight coincides with FCC complaint MORE (D-Ore.) that would block exporting oil brought into the country through the controversial pipeline.
Also to be considered is an amendment from Sen. David VitterDavid VitterObama: Louisiana flooding 'not a photo op issue’ Louisiana senator calls on FEMA to open recovery centers Ryan's victory trumps justice reform opponents MORE (R-La.) to extend oil and gas drilling permits in the Outer Continental Shelf, and one from Sen. Bob CorkerBob CorkerBolton would consider serving as Trump's secretary of State Trump struggles to land punches on Dems over ISIS GOP senator: Trump calling Obama ISIS founder 'went far too far' MORE (R-Tenn.) to reduce the 2013 discretionary spending cap.
Several of the measures will require 60 votes to be approved.
Democrats have framed relenting on amendments as the only way to move forward in the Senate on the transportation bill, which even Republican leaders in the House have publicly acknowledged could end up forming the basis of a final authorization measure that becomes law.
"I was hoping we wouldn't have to face convoluted amendments that are completely non-germane amendments, but they are insisting on them, so we'll have to deal with those," Sen. Barbara BoxerBarbara BoxerFeds weigh whether carbon pollution should be measured in highway performance Juan Williams: Dems should not take Latinos for granted Reid faces Sanders supporters' fury at DNC MORE, the chairwoman of the Senate Environment and Public Works Committee, who has shepherded the transportation bill to the Senate floor, said in a press conference Wednesday.
"It probably would be rolling back Clean Air Act rules," Boxer said of the amendments to the highway bill. "I can't imagine why anyone would want to do that, but there are some that want to do that."
The Senate began consideration of the highway bill amendments at 9:30 Thursday morning. The chamber is expected to resume debating the measure at about 10:45.
— Pete Kasperowicz contributed to this report.