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What to Know About the Entrance to Aspen; Council to Host Work Session

What to Know About the Entrance to Aspen; Council to Host Work Session

The date when the Aspen City Council will again take up perhaps the city’s longest-standing controversy — going all the way back to those S-curves installed in 1891 — is fast approaching.

Next Monday, Feb. 13, the council will host a work session on the results of the city’s outreach on the aging New Castle Creek Bridge. Next-step recommendations are expected to be announced at the meeting.

Here is a brief overview:

The Castle Creek Bridge was built in 1961 with an estimated lifespan of 75 years. This will expire in 2036. In 2022, the Colorado Department of Transportation rated the bridge as “fair” with a score of 50.3 out of 100.

Once a bridge falls under the 50.0 threshold, it will then be deemed “poor.” In this scenario, CDOT could put weight limits on vehicles crossing the bridge for safety reasons.

CDOT officials say they will not ignore the deterioration of the bridge and will invest the funds and work to maintain the community’s safety. However, maintaining an aging bridge takes lots of construction and patience. For example, the local community will remember the congestion from September 6 through October 13 in 2022 for needed repairs. It caused much longer commutes for the community.

The repairs still leave a deteriorating bridge nearing the end of its lifespan, officials said. It typically takes eight to 12 years to plan and build a new bridge.

Why not just build a new bridge?

This is where things get complicated. A new bridge is part of an entire new entrance approach to Aspen.

Entrance to Aspen

For more than 30 years, the city of Aspen, alongside community partners and local government agencies, has been discussing the transportation options in and out of town, dubbed the Entrance to Aspen.

Included in the discussion is easing traffic congestion in and out of the city, better preparing the community for natural disasters and hazards such as floods and fires, and lessening carbon emissions and air pollution.


A major factor are the S-curves, which date back to 1891. When Pitkin County decided to build a bridge into town, officials chose the current location because the Colorado Midland Railroad was already coming into town on a trestle over Castle Creek, entering on what is now a pedestrian bridge.

A large smelting operation known as the Lixiviation Works (now the Holden-Marolt Museum) was in this location as well, inhibiting a direct link to Main Street. As the population and vehicle travel have grown in Aspen, the S-curves have helped create daily bottlenecks.

These S-curves limit traffic to 700-800 vehicles per hour that can navigate through them. The current traffic alignment and travel patterns impact neighborhoods. Backups push outbound traffic into the West End neighborhood — causing safety issues and disruption for residents — as well as well into East Main, gridlocking the downtown core.

Why not build more public transportation to ease the vehicle load? Trackless trams, light rail, or other modern forms of transit can’t be implemented with the S-curves due to the lack of space in town, officials say.

But there remain plans someday to bring light rail in the final configurations approved in the Record of Decision.

That leaves Aspen today with an aging bridge and two options.

Option 1

Option 1 is leave the bridge as is. The Castle Creek Bridge remains the primary entrance and exit to Aspen. This requires frequent repairs, likely vehicle weight limits, and would impact commercial deliveries as the bridge further deteriorates.

When more drastic repairs are needed, CDOT and the Federal Highway Administration are looking to the Aspen City Council for support of the Preferred Alternative, so that a New Castle Creek Bridge can be constructed. CDOT and FHA officials declare they will always ensure the safety of the bridge regardless of which option is chosen.

With option 1, Power Plant Road would need to be widened and re-aligned, so that it could serve as a detour during extensive repairs or reconstruction of the old bridge. This project could take 18 to 24 months.

Along with this option, the rebuilt bridge would remain at two lanes due to the existing bridge infrastructure — the piers and foundation that hold it up.

Option 2

Option 2 is the Preferred Alternative and much, much more complicated. The 1998 Record of Decision issued by CDOT would re-align Highway 82 across the Marolt Open Space on the west side of town.

The Preferred Alternative would include two general-use lanes and two exclusive bus lanes that could accommodate light rail or trackless trams in the future. This also includes a new bridge over Castle Creek along the new alignment. This would increase transit capacity while decreasing transit time with continuous bus lanes from the roundabout to downtown.

The Preferred Alternative also dictates that the highway across the 82-acre Marolt-Thomas properties would cover 5.4 acres, and 2.5 acres would be gained from the land bridge and decommissioned Highway 82 between the roundabout and Cemetery Lane.

The land bridge would allow for pedestrians and wildlife to more safely cross over Highway 82.

The existing Castle Creek Bridge remains in use as a local connection to the Cemetery Lane neighborhood and McLain Flats.

If option 2, the Preferred Alternative, is chosen, CDOT, the FHA, and the city of Aspen will engage the community about details such as pedestrian infrastructure and access, aesthetics, and open-space planning that includes the land-bridge design, officials say.

In 1996, Aspen voters authorized approval for a two-lane parkway and a corridor for light rail.

Now, Aspen voters would be asked at some point to approve buses through current open-space area. The City Council hasn’t decided when to put this question to the voters.

If the Preferred Alternative is chosen, the existing Castle Creek Bridge will be used while a new bridge is constructed and then later reconstructed as an additional entrance/exit from downtown.

Officials said the Aspen community needs to understand that, to build a new Castle Creek Bridge, it is currently packaged with the Preferred Alternative.

Next Monday, the City Council will hear a summary of the outreach and staff’s recommended next steps.

Elements of the Record of Decision that have been completed as of 2022:

  • Maroon Creek Bridge.
  • Roundabout.
  • Pedestrian overpasses over Maroon Creek and Castle Creek roads. 
  • Harmony Road underpass and intersection improvements.
  • Owl Creek Road realignment and new signals at Highway 82 at Buttermilk Mountain. 
  • Main Street bus lane addition.
  • New signals on Highway 82 at Buttermilk. 
  • Conveyance of right-of-way. In 1996, Aspen voters approved an easement across Marolt-Thomas Open Space for two lanes and a light rail in exchange for Mills Ranch property as open space.
  • Transit Management Program. Programs and policies encourage people to use the bus, bike, or walk.
  • In addition, the city of Aspen implemented additional programs with the intent of increasing the use of alternative modes of transportation. These include: Main Street bus lane; Roaring Fork Valley car-share program; carpool matching and parking programs; Transportation Options Program that provides grants and other benefits to employers.

Elements of the Record of Decision remaining: 

  • Parking structures.
  • Open space connection to Aspen Golf Club.
  • Land bridge.
  • New Castle Creek Bridge. 
  • Right-of-way improvements on Main Street.

For more information, visit aspen.gov.

By: Julie Bielenberg I Aspen Times I February 6, 2023

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