A bipartisan group of four key senators has reached agreement on the outline of a six-year, $339.2-billion surface transportation measure.

The deal was announced on May 25 by Senate Environment and Public Works Committee Chairman Barbara Boxer (D-Calif.), along with the committee's ranking Republican, James Inhofe (Okla.), transportation and infrastructure subcommittee Chairman Max Baucus (D-Mont.) and the subcommittee's ranking Republican, David Vitter (D-La.).

The accord signifies progress on legislation long-awaited by the construction industry. But there is still a long way to go.