Getting Texas 360 extended from Arlington to Mansfield beginning in 2015 became more realistic Friday after the North Texas Tollway Authority approved a deal to develop the toll project in a partnership with another agency.Texas 360 will be extended as a toll road from Sublett Road/Camp Wisdom Road to U.S. 287, with the Texas Department of Transportation doing the initial design and construction and then turning over the road to the tollway authority to be operated and maintained as part of the region's now-vast tollway system.The breakthrough, approved Friday by the tollway authority board during a special meeting, was cheered by Mansfield and south Arlington residents, who for years have been trying to call attention to the need for traffic relief in the Texas 360 corridor. It's one of only a handful of north-south options for thousands of commuters per day trying to get from the thriving residential areas of Arlington-Mansfield to jobs in the center of the Metroplex."Traffic congestion on 360 is a serious quality of life, economic and safety issue for families and businesses in southeast Tarrant County," state Rep. Chris Turner, D-Grand Prairie, said in an email. In 2009 and 2010, Turner organized community leaders in Arlington, Grand Prairie and Mansfield to work together to see the Texas 360 project through to completion."Today's decision by the NTTA," he said, "is a significant step forward in solving this problem."Terms of the agreement must still be approved by the Texas Transportation Commission, which plans to take up the issue at its February meeting in Austin. After that, officials from the two agencies would have until the end of March to finalize a development agreement.An environmental study must also be completed. But it's realistic to expect that the road could be under construction by 2015 and open to motorists by 2017, said Bill Meadows of Fort Worth, a transportation commission member who has worked on the agreement for several years.The sooner the better, Mansfield City Manager Clayton Chandler said."Anybody who's driven on Highway 360 recently at peak times knows that it was needed several years ago," Chandler said. "We've got schools on 360, we've got businesses on 360, we've got land that can't develop on 360 because they have no access. We really can't go any longer without expanding that highway."Expansion plansThe initial phase of construction is expected to cost about $600 million. The state transportation department can pay for the work with project-backed debt, a federal transportation infrastructure loan or cash from the state's highway fund, according to the agreement.The road would be expanded to four main lanes as far south as Broad Street and two main lanes from Broad Street to U.S. 287. Frontage road improvements are also in the mix.Any toll revenues left over after the debt, operations and maintenance expenses are paid will be split evenly between the two agencies.The state will focus its share of the funds on improving the Texas 360 corridor north of the project. For example, some of the funds could eventually be used to improve the old looping turnpike interchange at Texas 360/Interstate 30, although a timetable for such work isn't spelled out.The tollway authority has dramatically expanded its role in providing mobility options for North Texas motorists during the past decade, beginning with the Sam Rayburn Tollway in Denton and Collin counties.The tollway authority also extended the President George Bush Turnpike into Grand Prairie and Irving, and inked a deal to build the Chisholm Trail Parkway from downtown Fort Worth to Cleburne.Avoiding more debtArranging all that work comes at a whopper of a cost.The tollway authority is now servicing $9.5 billion worth of debt and, although it probably could have issued more, didn't want to go deeper in the red to build the Texas 360 extension.So, the next best thing was to tap into the borrowing power of the Texas Department of Transportation, and that's the essence of the agreement reached Friday."It preserves our funding to use on future roads as they come up," said tollway authority board member Victor Vandergriff of Arlington, who will be leaving the board at the end of the month.The tollway authority gets to add Texas 360 to its growing portfolio of toll roads.The Texas Department of Transportation gets the benefit of traffic relief at essentially no cost.And Texas motorists will get the immediate benefit of a road expansion that, were they left to use only traditional forms of funding, they might not be able to afford for another 20 years.-- News-Mirror writer Robert Cadwallader contributed to this report.