CDOT releases final environmental study on I-70 improvements |

CDOT releases final environmental study on I-70 improvements

Caddie Nath
Summit Daily News
Aspen, CO Colorado
CDOTMap of the I-70 mountain corridor.

DENVER – The Colorado Department of Transportation released a final environmental study Friday, evaluating possible alternatives for long-term improvements to the Interstate-70 mountain corridor including the $16 billion to $20 billion “preferred alternative” presented in September.

The final Programmatic Environmental Impact Statement (PEIS), which does not include any big deviations from draft PEIS released in September, is an analysis of 21 distinct proposals for improvements to the corridor as well as a no-action alternative and their potential environmental effects.

“There are no major changes from the draft document with what the vision for Interstate 70 is,” CDOT spokesman Bob Wilson said. “It was all more clarification (in the final PEIS).”

The 527-page study will be reviewed by CDOT and the Federal Highway Administration and followed by a record of decision, selecting one or a combination of multiple alternatives evaluated in the PEIS.

The record of decision will likely be released in late May or early June, Wilson said.

Among the improvement options evaluated in the PEIS is a proposal dubbed the preferred alternative, an option calling for extensive long-term improvements and projects in the corridor, including a high-speed rail providing service between Denver and the corridor.

The preferred alternative combines three separate components to improve traffic on I-70: The high-speed rail, known as an Advanced Guideway System, highway improvements, including widening the highway to six lanes between Floyd Hill and the Twin Tunnels and auxiliary lanes approaching the Eisenhower Tunnel from both directions and non-infrastructure strategies such as programs for commercial truck travel and bus or shuttle service.

All but one of the action-based alternatives examined in the PEIS would require new bores through the Twin and Eisenhower tunnels, according to study documents.

The preferred alternative is among the most expensive of the 21 options evaluated in the study, which ranged from just under $2 billion (a minimal-action alternative) to more than $20 billion (proposals involving a high-speed rail).

There is not enough funding to implement the preferred alternative, though the department recommends a corridor improvement project be given high priority in the state to attract funding. The study lists tolling and public-private partnerships among possible funding sources for the proposed alternatives.

Alternatives for the mountain corridor and the PEIS stemmed from a significant increase in traffic on the already-congested Interstate expected over the next two decades.

By 2035, traffic volumes are expected to triple weekend travel time from 2000, while weekday travel time would be more than double what it was in 2000 without improvements, according to data included in the study.

The PEIS was compiled and the preferred alternative formulated with input from stakeholders, individuals and local governments along the corridor. Organizations like the I-70 Coalition also participated in the long study process.

“The I-70 Coalition is excited to see this PEIS process reach a conclusion,” coalition chairperson Michael Penny said in an e-mail. “We are especially grateful to the previous CDOT Director Russell George for pulling together the Collaborative Effort that allowed us to reach consensus on the future direction of the I-70 improvements. It was an open and inclusive process that allowed all stakeholders along the corridor to participate.”

Recommendations from the Collaborative Effort, a 27-member group of corridor representatives, is reflected in the final PEIS, according to a CDOT statement.

The PEIS also includes a nearly 700-page appendix responding to hundreds of comments from organizations, local governments and individuals submitted during a public comment period that followed the release of the draft PEIS.

The final PEIS will be available for review at 26 CDOT locations and online at until April 11. During the review period CDOT and federal highway representatives are available to present information on the study to small groups. Contact Wendy Wallach, CDOT’s environmental manager for the mountain corridor at (303) 757-9008 or by e-mail at

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