The Dallas metro area's light rail network, already the country's largest with some 85 miles of track serving 13 cities in a 700-sq-mile area, is still growing. When Dallas Area Rapid Transit (DART) completes the system's latest expansion, expected in 2014, it will exceed 90 miles of track—nearly double what it was just five years ago.

The system's growth trend took a major jump in December 2010 when DART opened its Green Line, a $1.8-billion project that expanded the rail network by 28 miles. Two years later, the $360-million, five-mile Blue Line extension from Garland to Rowlett opened. The first two sections of the $1.3-billion, 14-mile Orange Line also opened in 2012, and work on a $150-million, 5.2-mile final section is now under way and set to finish by the end of next year.

With completion of this last portion of the Orange Line, the DART rail network will nearly double in size from 48 miles before 2009. For its efforts in managing smart growth, focusing on its stakeholders and customers, championing sustainable and innovative practices and embracing extensive collaboration with its contractor teams, ENR Texas & Louisiana has named DART its 2013 Owner of the Year.

Contractor Collaboration

A 24-mile starter line that opened in 1996 introduced Dallas area residents to the concept of light rail.

"If you do too little initially, people don't really embrace or understand the value of it," says Gary Thomas, DART president and executive director. "But now, our biggest challenge is how we can build more sooner. People have really embraced the concept of having a transportation choice along with the economic development that comes with the light rail system."

In building out the system over the past two decades, DART has shifted its approach toward contractor partnerships and project delivery. For the first 20 years, DART was a design-bid-build agency. But following the Green Line expansion, the agency decided to change its project delivery method and look at more of a best-value type of contracting, says Tim McKay, DART's executive vice president of growth and development. "So we went to a construction manager-general contractor approach," he says. "At the time, ours was the longest light rail project in North America that was under construction. The balance in 2010 was about 24.5 miles, and that really got us postured to think about design-build."

DART turned to design-build on the Orange Line and the Blue Line extension projects "largely because we were interested in speed and taking advantage of a very good owner's market," McKay says.

A joint venture of Kiewit Cos., Stacy and Witbeck, Reyes Group and Parsons Transportation Group was contracted to complete all three Orange Line segments, while Austin Bridge & Road took on the Blue Line project. "DART was really wanting to work closely with the contractors and the designers, listen to them closely and work to make the experience successful, and it did that," says Dale Stubblefield, Austin Bridge & Road's vice president of business development. "Certainly DART pushed us to come up with some creative answers, and there were times when we came back to [the agency] and said here's a better way to do it, and eventually as a team we came up with the best solution."

Innovation

Many opportunities arose during construction on the Orange Line project for DART and its contractor teams to develop new solutions, aided by the design-build process.

"We were afforded the ability to be innovative," says Steve Medina, officer-in-charge of team managing partner Kiewit. He says that on the current third section, "we used a pinch-point innovation, which involved taking the alignment from one side of the airport's current North Airfield Highway and moving it to the other, which eliminated bridges, caused crossings to be safer and at the end of the day, reduced the scope of work."

On the previous two portions, the team also had to contend with crossing the Trinity River Levee. "We wanted to be able to go over the levee without penetrating it, and we also wanted to stay under a series of power lines—the concept was called 'thread the needle' by the design-build team," McKay says. That approach gave the team a $2-million advantage—equivalent to the cost of moving the power lines if traditional approaches had been used.