Update April 18, 2012: The Associated Press reports that President Barack Obama will threaten to veto transportation legislation if a mandate to complete the Keystone XL pipeline is attached to it. Please read the article here.

The House Rules Committee will meet later this afternoon to discuss the possibility of yet another extension to the highway and transit bill.

The legislation being considered would give a 90-day extension to the latest bill, scheduled to expire at the end of June. But it could ultimately pave the way for longer-term extension.

Back in March, the Senate passed a two-year, $109 billion highway and transit bill. The House has failed to pass its own legislation -- a five-year, $260 billion bill -- that has been opposed by Democrats and has split the Republican ranks.

Most observers are speculating that if the House ultimately passes this 90-day extension, it could be used as a vehicle for the House to enter conference committee negotiations with the Senate. That would be significant move forward for transportation legislation, since the House's own lack of progress has prevented that step so far.

Additionally, Democrats have offered the Senate's legislation, known as MAP-21, as an amendment to the House's temporary extension in hopes that the Rules Committee would allow a vote on the bill.

The House could vote on the extension this week if the Rules Committee gives it the green light.