Colorado is struggling with a problem that's common across many states - the population continues to grow and roadways designed long ago just can't keep up. "You'd hope people could use different forms of transportation or shift their work schedules," says Mike Keleman, P.E., Project Director and Express Lanes Resident Engineer for the Colorado Department of Transportation (CDOT), before adding what engineers around the country already know. "Everyone hopes the person in the car next to them is doing that because theyare not doing it."

But the lure of telecommuting and the availability of mass transit can only do so much. Colorado Department of Transportation's (CDOT) figures show that the section of Colorado State Highway 470 that stretches south of Denver, from Wadsworth Boulevard in the west to I-25 in the east, already serves more than 100,000 motorists each day. By 2035, they estimate those numbers on C-470 will increase 40 percent.

The C-470 Express Lanes project is one way CDOT is working to prepare for that additional growth. "We're adding express lanes to C-470, with the goals of reducing congestion and increasing trip reliability," Keleman says of the 12.5-mile stretch covered by the project. Commuters today don't know how long their trip will take, since the normal traffic flows on C-470 can quickly turn into jams. "If you're going to work or coming home, you'll have the option to jump into one of the express lanes and you'll know you'll get there in the time we say you will," Keleman explains.

Along with adding the tolled express lanes - up to two new lanes for portions of the westbound section and one lane eastbound - the project will provide several other important benefits. Auxiliary lanes will be added between several interchanges and on- and off-ramps will be reworked. "We see traffic backs up at the ramps because people are slowing," Keleman says. "We'll now have parallel merges instead of cutting straight into traffic, so flows should be improved." The planned reconstructions also offer CDOT the opportunity to realign a number of substandard curves. In addition, several bridges along the project's length will be widened, and bridges over the South Platte River will be replaced.

Outside the flow of automobile traffic, Keleman says work is also being done on the nearby multi-use trail. "It's a pedestrian and bike path, and there's also a lot of equestrian use," he says. The trail runs the length of the project, and underpasses are being added at key locations to improve safety. "Right now, if you're on the trail you come up to a stop light and you have to wait and then cross," Keleman explains. "It will be much safer with the new crossings under the roadway." The trail is heavily used and CDOT is working to minimize the disruption to cyclists, walkers, joggers and equestrians while the changes are made. "While most of the project's money is going toward the highway and adding lanes for drivers, the trail users have an equal voice," Keleman says.

The C-470 Express Lanes project's $276 million construction costs are funded through various sources. Funding at the federal, state and county levels will cover about $120.6 million, and loans repaid through toll revenue bonds will pay for the remainder. "This project wasn't just based on the lowest bidder," Keleman says. "It's a design-build job, and the dollar amounts were weighed alongside the design-build team's proposal." Given the scope of the project and its long-term impact to drivers, CDOT was committed to gleaning the best value overall.

Thoughtful Project Oversight Boosts Sustainability

Workmanship quality has been a primary focus for the C-470 Express Lanes team. One way they've been able to maintain their high standards across such a sprawling and multi-faceted project is by diligently and thoughtfully managing their available resources. "If we have one aspect of the job where the contractor and designer have done good work, we've relaxed some of the inspection activities on that part of the project because they've proven time and again they can perform their work well," Keleman explains. Rather than adhere to a standard protocol that calls for 10 inspections, for example, a high-performing contractor may require only one or two.

The team implemented the change shortly after beginning the project, when they realized they were tight on resources and that a number of activities were going extremely well. "We got to a level of comfort that these contractors could perform their activities with a high degree of quality," Keleman says. The result is that experienced contractors are able to quickly move from one task to the next, and the team's inspectors are better deployed in other areas of the project that may require more attention. "It's been useful to refocus those resources," Keleman says.

Environmentally-minded Colorado has been a perfect setting to pursue sustainable construction practices throughout the C-470 Express Lanes project. For example, where contractors are removing the existing concrete, they're rubblizing much of it and recycling it into new pavement sections. "That's unique, because usually on other projects you really focus on the mix design and rarely do you get materials contractors who are willing to put in that unknown of recycled material," Keleman says.

Another green approach involves the sizable number of existing pipes - drainage, storm, sewer - that span the length of the project. CDOT is working with their contractors to keep recently constructed systems in place where inspections confirm sound infrastructure. This approach minimizes impacts in constrained areas where feasible, and reduces the environmental burden associated with sending additional materials to the landfill.

Good Communication Keeps Drivers Up to Speed

Keleman says the area has been blessed with a mild fall, and they haven't yet had to contend with the winter weather difficulties Denver and its surrounding communities often experience. "We're trying to take advantage of that and get caught up on paving operations now," he says. But even though weather hasn't been a big issue so far, Keleman says that communicating with the public - about lane and bridge closures, detours and similar updates - is a top priority for the team. The project's website has been a good source of news for drivers, with the CDOT team constantly ensuring the data is accurate and up-to-date.

Most of the project's closures are at night, but whenever activities are likely to impact travelers, Keleman says, "It's all about public information. We use CDOT's extensive system of message boards to tell drivers about any work that's upcoming and any detours we have set up." E-mails are also sent to other stakeholders, from cooperating agencies to the media, to help spread the news. The wide communication net, coupled with a close partnership between the project team and its supporting contractors, has helped keep all the components of the complex C-470 Express Lanes project on track. "If you have a very good team, you can do good things," Keleman says.