A new I-25 bottleneck

CDOT's plans to fix post T-REX tie-ups face hurdle: money

Kevin Flynn, Rocky Mountain News

Monday, November 27, 2006

The completion of the T-REX highway project has moved Interstate 25's bottleneck north to Santa Fe Drive, where the new road ends and the traffic jams now begin.

Planners have completed work on an environmental study that outlines how to fix that. All they need is money, but dollars for the work are in short supply, and the project probably won't begin for several years.

The T-REX project that just wrapped up spent $809 million improving 17 miles of I-25 from Broadway south to Douglas County and up Interstate 225 to Parker Road in Aurora.

Motorists who once got stuck in the Narrows of I-25 in south Denver or in the busy Tech Center stretch now can fly through there until they reach the new pinch point on the north side of the Broadway bridge.

That's where T-REX's new fourth lane northbound disappears onto the Santa Fe exit ramp. The merging traffic forms a rush-hour accordion that often backs up to University Boulevard. Likewise, the southbound direction loses a fourth lane at Santa Fe.

The three-lane distance is short, only several hundred yards, but the effect is maddening.

The new study, called the Valley Highway Project, has assembled a package of improvements to I-25 from Broadway to Sixth Avenue, and out Sixth to Federal Boulevard. The cost is pegged at $294 million in today's dollars.

The centerpiece is the addition of one more lane in each direction of I-25 from Broadway through Alameda Avenue to eliminate the bottleneck and keep traffic flowing.

That will be neither easy nor inexpensive. Widening requires a complete reconstruction of the outdated and busy interchange of I-25 and Santa Fe - while maintaining traffic flow during construction.

The I-25 bridges over Santa Fe date to the 1950s. Santa Fe sits between the northbound and southbound lanes of I-25, a design that gives the freeway two hazardous left-lane on-ramps.

The new plan reunites I-25 into a single overpass. Access to and from Santa Fe would be by way of an intersection with a traffic signal - with one exception. Northbound Santa Fe traffic headed onto northbound I-25 would have its own two-lane flyover ramp for a nonstop flow onto the freeway, similar to I-25's southbound ramp onto I-225 built as part of T-REX.

The project also calls for a number of improvements drivers have awaited for decades - eliminating the railroad crossings at Santa Fe and Kalamath Street, widening the Alameda overpass for better I-25 flow under it, improving the Alameda interchange, upgrading the Sixth Avenue Freeway between Federal and I-25 and eliminating the hazardous Bryant Street ramps near Federal and Sixth.

But don't expect any improvements soon. The obstacle is money.

"We had a shot at it with Referendums C and D," said Tony Gross, the Colorado Department of Transportation's project manager on what it calls the Valley Highway Project. Ref C passed, but voters rejected the highway bonds in Ref D.

While Ref C has allowed more money to flow into the state transportation budget, dozens of projects are already in line ahead of this new work.

So CDOT is trying something new.

Normally, the Federal Highway Administration won't sign off on an environmental study like this until the state has locked in the money for the entire project. CDOT is pioneering a new process of phased approvals, breaking out parts of the overall work that can stand on their own and trying to fund them piecemeal.

The Santa Fe work, considered the most critical, is being packaged in phase one along with improvements at the hazardous Bryant Street eastbound on-ramp to Sixth Avenue.

While both of these projects are listed on the region's long-range highway plan, they are not yet on the short list for funding. That step is crucial to getting federal approval to start phase one.

The rest of the Valley Highway Project's pieces aren't even on the long-range plan yet.

If it all gets built, some of the last remaining vestiges of the original Valley Highway, built between 1948 and 1958, would fade into history.

"You look at the old Valley Highway, and you had to wonder about all those little hook ramps all over the place," Gross said. "We learned a few things about highway design in the last 50 years."

Valley Highway project

These are the major elements of the proposed $294 million package of improvements to Interstate 25 and Sixth Avenue in Denver:

• Rebuild the Santa Fe interchange and provide four I-25 lanes in each direction; $84 million

• New on-ramps from Federal Boulevard to Sixth Avenue Freeway, close Bryant Street ramps; $23 million

• Rebuild the Alameda interchange with flyover bridges that put all the access ramps on the west side of I-25; $23 million

• Move the railroad tracks slightly east to allow widening of I-25 between Alameda and Sixth; $36 million

• Eliminate the railroad crossings on Santa Fe Drive and Kalamath Street north of Alameda by putting both streets under the tracks, $36 million

• Rebuild the Sixth Avenue Freeway and bridge over the South Platte River; construct a bridge to take the Federal ramp to eastbound Sixth over the exit ramp to I-25, $77 million

• Reconfigure the Broadway-Lincoln Street interchange on I-25; $15 million.

What's next

• A public hearing on the Valley Highway Project environmental study is scheduled for Thursday from 5:30 to 8 p.m. in Drury Gymnasium, 375 S. Zuni St. The study can be viewed online at www.ValleyHighway.com.

flynnk@RockyMountainNews.com or 303-954-5247