Democrats on the House Transportation and Infrastructure Committee told President Obama they have "profound disappointment" that he called for a short-term extension of the current transportation bill instead of backing a more comprehensive overhaul this year.

Rep. James Oberstar (D-Minn.), the committee's chairman, and 42 other Democrats wrote a letter to Obama Thursday pressing him to consider their $500 billion proposal to fund new road and rail projects for the next six years.

The White House has said it wants to extend the current bill for at least 18 months.

"Your proposal fails to acknowledge the severity and urgency of the challenges facing the nation's surface transportation system at this critical time," the House members wrote. "It will lock us into the discredited policies of the past and prevent us from moving toward the transporation system of the future."

(Read the whole letter here.)

The expiring bill, passed in 2005, runs out at the end of September.

Oberstar and other public transit advocates want new legislation that put more emphasis on mass transportation and a comprehensive approach to making travel safer and more efficient.

Surface transportation bills in the past have been derided as vehicles for earmarks and have been criticized for lacking a coherent plan to address failing infrastructure and increased traffic.

The current transportation bill, which cost nearly $300 billion over more than four years, raised tensions between the previous administration and lawmakers. President George W. Bush in 2005 had called on Congress to cut down on spending in the bill, while many members were willing to fight earmarks sending more money back to their districts.

The resulting standoff between Bush and Congress lasted until July 2005, months after the previous legislation it was supposed to replace was set to expire.