Cover Story — May/June 2006

Reinventing a Corridor

Denver's T-REX project nears completion after five years

By Mark Shaw

One of the T-REX construction milestones was the rebuilding of the outdated I-25/I-225 interchange to include a flyover and grade-separated light rail lines. Courtesy of CDOT

Denver commuters are eagerly awaiting the end of an era this summer-the departure of an unwieldy dinosaur that has squatted in the heart of their city for five years.

T-REX, the region's $1.67-billion transportation monster, is pushing steadily toward a fall completion. Construction on the combined highway and transit project will be complete Sept. 1, with light rail service beginning in mid-November.

T-REX-short for Transportation Expansion Project-includes 17 miles of highway improvements to Interstates 25 and 225 in south Denver, including extra freeway lanes in all segments of the corridor and rebuilding several troublesome interchanges and outdated bridges. The project also creates 19 miles of new double-track light rail built in the highway corridor and paralleling both freeways.

"The multi-modal approach gave us an opportunity to look beyond our traditional highway-transit boundaries and solve problems together in a bigger way," says Cal Marsella, general manager and chief executive officer of the Denver Regional Transportation District. "Also, we probably saved around $300 million doing it as a combined rail and highway project."

The T-REX southeast corridor light rail will run along the west side of I-25 from south of downtown Denver to the city's southern suburbs in Douglas County. A spur line will stretch northeast along the center median of I-225 into the eastern suburb of Aurora. The transit system includes 13 new light-rail stations and improvements to the existing Broadway station on the north end, the purchase of 34 light-rail vehicles, a new maintenance facility and a communications control center.

The southeast rail line will connect to Denver's existing light-rail lines that service downtown and the southwest suburbs. RTD officials estimate that southeast corridor trains will immediately service more than 38,000 riders a day, with the option of adding more trains and increasing frequency to meet RTD's forecast of 51,100 to 59,800 weekday riders in the southeast corridor by 2025.

Where freeway segments had to be completely rebuilt, crews from Southeast Corridor Constructors repaved them with concrete. Courtesy of CDOT

Despite a demonstrated need for more transportation capacity in the corridor, some locals initially were skeptical of the multi-modal approach. They wanted to add lanes to the freeways and put off construction of light rail until later.

"But delaying the light rail would have made it more like a 15- to 20-year build-out," Marsella says. "It would not have been done nearly as well, and at tremendous cost, had we waited and added it later."

"Without a doubt, we saved millions by doing the highway and light rail together, by having them physically sharing the same corridor," says T-REX project director Rick Clarke. "I couldn't possibly speak to all of the benefits that decision has brought, but just the research and right-of-way savings alone were tremendous."

Easing Congestion

T-REX construction was done under a design-build, guaranteed-maximum-price contract of $1.18 billion over a five-year schedule. As of early summer, the project is on time and within budget, says Tom Howell, project manager for the contractor, Southeast Corridor Constructors, a joint venture of Kiewit Construction, Omaha and Denver; and Parsons Transportation Group Inc., Denver. "We're going to hit our number and our date," he says. "In fact, the light-rail system will open about a month earlier than projected." The T-REX light rail grand opening is scheduled for Nov. 17.

"I don't know of a project in my 34 years in the business that's gone better than this one," says Tom Norton, executive director for the Colorado Dept. of Transportation. "It will solve a lot of problems for Denver commuters who navigate the south end of I-25 every day to and from work."

Denver's I-25 southeast corridor is the most congested area in Colorado, CDOT says. I-25 links Denver's two major employment centers-downtown and the Denver Tech Center-where more than 200,000 people work. Regional growth will add another 150,000 jobs in DTC and downtown over the next 20 years, says the Denver Regional Council of Governments, a multi-county oversight group.

The T-REX team worked with dozens of municipalities to develop light-rail stations that enhanced their communities and stimulated interest in transit-oriented development. Courtesy of CDOT

CDOT reports that I-25 carries more than 230,000 vehicles through the area every day, and the southeast corridor includes the I-25/I-225 interchange, once identified by the U.S. Dept. of Transportation as the 14th most congested interchange in the country. The southeast side of the Denver metro area is also a booming residential area, with the Census Bureau ranking Douglas County as one of the fastest growing counties in the U. S.

All of these factors led transportation planners to decide that simply adding lanes to the freeways was not likely to solve the congestion. Using both light rail and expanded highway capacity seemed to be the best solution, but the multi-modal nature of the project presented its own complications: How to incorporate a mass transit component into an already crowded space? How to build this ambitious project safely and efficiently while the number of vehicles using the corridor increased every month? How to make all of the infrastructure corrections at the same time?

More than a dozen bridges, many built in the 1950s, needed to be replaced, expanded or repaired. The outdated I-25/I-225 interchange had to be completely rebuilt, and drainage on I-25, a problem for decades, had to be fixed.

The answers evolved from a number of arenas. First, the T-REX team established a set of goals to guide its decisions, with public safety and convenience at the top of the list. "We realized early on that there was no viable alternative to I-25 through that corridor," Norton says. "There were no other arterials big enough to handle that volume of traffic if we wanted to shut down the freeway during the day. So the alternative to I-25 had to be I-25."

New Light-Rail Maintenance Facility The 125,000-sq-ft, state-of-the-art Elati Light Rail Maintenance Facility is where all of the Regional Transportation District's light-rail fleet will be cleaned, maintained and inspected, including the 34 new vehicles being added to the system through T-REX. The Elati facility was designed and constructed using openness, natural light and aesthetic treatments on the interior and exterior of the building. Built by Denver's M.A. Mortenson, it includes a train washing station, wheel-truing lathe area, sanding pump station and several maintenance bays. © LaCasse Photography

That meant keeping at least three through-lanes of the freeway in both directions open from 5:30 a.m. to 8:30 p.m., with infrequent highway closures at night for utilities, bridge work and paving. T-REX planners phased the highway expansion to keep traffic moving through the corridor during the day, but that required some design and scheduling flexibility.

"We couldn't have solved all of those problems and stayed on schedule without using design-build," says Del Walker, T-REX deputy director. "Overall design was about 35% complete when we got started, and as it evolved, that allowed us enough flexibility to move quickly through changes as we went along."

Other critical elements included a proactive quality management program and an aggressive public relations strategy and public involvement process. And the fact that all T-REX team members were based in a central office helped foster the feeling that they were T-REX employees, whatever their agency roots.

"We created a brand new organization out of three different cultures-CDOT, RTD and the consultants," Clarke says. "We created a T-REX culture."

They carried T-REX business cards and learned to solve problems as a team. "There were no issues resolved outside of the T-REX team," Clarke says. "No heavy-handed oversight from our respective agencies. We intentionally picked people for T-REX who could handle that approach."

Marsella and Norton and their agencies supported the team atmosphere. "We insisted upon the structure of a completely separate entity," CDOT's Norton says. "That wasn't always easy for me, or for others here at CDOT, to rein ourselves in and not meddle, but we realized it was the only way for the T-REX team to function like they needed to."

The team worked with dozens of municipalities and businesses to develop designs for the light-rail stations that enhanced their neighborhoods and afforded the best opportunities for transit-oriented development along the corridor.

"This project generated a tremendous amount of transit-oriented-development interest at almost every station," RTD's Marsella says. "It was a real learning experience for some of the communities, and T-REX was an important part of that learning curve. But we're not in the development business, so we tried to educate people on the other side to make that happen. Ultimately, I think this project will transform Denver, and the model it creates will help other cities who may want to do the same thing."