Lawmakers involved in the talks said they expected to present their report late Wednesday or early Thursday, with a House vote on Thursday.
The bill would provide $286.4 billion in the 2004-2009 period, replacing the $218 billion six-year program that expired in September 2003.
Passage has been a priority of this session of Congress and the last. But lawmakers have failed to resolve disputes with the White House over spending levels and with states over the distribution of federal highway money.
"Given the inadequate top line, it's a pretty decent bill," said Oregon Rep. Peter DeFazio, the top Democrat on the House Transportation and Infrastructure subcommittee on highways. He was one of many lawmakers who had sought significantly higher spending.