After Colorado Transportation Commission members were briefed today on a recommended congestion-relief measure for Interstate 70’s Twin Tunnels area, commissioners turned to the next question — how to pay for the $55 million project.
Colorado Department of Transportation engineers detailed for commissioners results of a workshop last month that considered a number of short-term options for relieving congestion in and around the tunnels near Idaho Springs.
That workshop, which included construction and tunneling experts from around the country — and England as well — settled on the option of widening the eastbound bore of the Twin Tunnels to accommodate a third through-lane and improved shoulders, as well as redesign of the 45 mph curve in the eastbound lanes of I-70, east of the tunnels, so the roadway could safely support a 50 mph speed limit.
In addition to the tunnel expansion, this preferred option also includes a plan to add a third lane in I-70’s eastbound direction from the east side of Idaho Springs to the base of Floyd Hill.
CDOT, local government officials, local residents and many business interests have been looking for congestion relief in the I-70 mountain corridor for more than 10 years.
CDOT has spent at least $30 million over the past decade on a broad environmental study of possible transportation improvements for I-70 from C-470 to Glenwood Springs.
That comprehensive study, which is now being finalized, has proposed a range of highway and interchange improvements, coupled with an advanced guideway system that could include a monorail or more traditional rail technology.
Early estimates put the price tag for that comprehensive package of I-70 improvements at between $16 billion and $20 billion.
Faced with such a daunting number, CDOT officials are promoting the Twin Tunnels congestion-relief option as a way to begin incremental and potentially affordable improvements in the I-70 corridor.
Over the past six months, agency officials analyzed other options for short-term congestion relief, including one that could install a reversible “zipper lane” to speed the flow of eastbound travelers, especially on winter Sundays, when the corridor experiences some of its heaviest traffic.
CDOT regional director Tony DeVito told commissioners today that deployment of temporary zipper-lane barriers for a roughly 15-mile stretch of I-70 on winter Sundays might cost about $40 million. An alternative “hybrid” version of the concept, using a shorter 5-mile reversed-lane segment along with hardening the shoulders of the highway to handle peak-time traffic, would cost as much as $30 million, he added.
The advantage of the $55 million plan for permanent widening of eastbound I-70 near the Twin Tunnels is that it offers a year-round, around-the-clock expansion of road capacity compared with the more limited relief on only about 17 days a year that the zipper-lane or hybrid options offer, DeVito told commissioners.
After presentationes by DeVito and his fellow CDOT engineer, Peter Kozinski, Transportation Commission chairman Les Gruen asked CDOT Chief Financial Officer Ben Stein where money might be found to construct improvements for the Twin Tunnels area.
Stein said his office will perform that analysis if it gets a more formal proposal to do so.
Commissioner Gary Reiff proposed that CDOT staff members “come back with possible funding alternatives” for the Twin Tunnels project and how they would affect other projects on CDOT’s schedule.
Commissioner Doug Aden said he and his colleagues must consider whether I-70 mountain corridor congestion is among the “most critical we face” when compared with other congested corridors.
He noted as well that for the Twin Tunnels solution to move forward, it must be seen as a priority by the Denver Regional Council of Governments, which establishes transportation priorities in metro Denver, including Clear Creek County.
Aden asked if some sort of tolling option might also be possible as a way to help pay for the tunnel-area improvements.
Commissioner Steve Parker asked rhetorically whether representatives of the ski industry in Summit County might not have a stake in contributing to funding the Twin Tunnels improvements.
Commissioner Trey Rogers helped close out the discussion, saying that the transportation commission needed “to spend a little more time thinking strategically” about funding options for the initial phase of I-70 mountain improvements.
Jeffrey Leib: 303-954-1645 or jleib@denverpost.com
