New Castle Creek Bridge

Aspen's Transportation Future NCCB Logo

For more than 30 years, the City of Aspen, alongside our community partners and local government agencies, has been discussing the best transportation options in and out of Aspen - an effort known as the "Entrance to Aspen". Since the existing Castle Creek Bridge is nearing the end of its lifespan, it's time to get serious about building a new bridge.  

Current Work for the Castle Creek Bridge

The City has hired Jacobs Engineering to assess the existing Castle Creek Bridge and provide the city with a Colorado Department of Transportation-style bridge evaluation report, including a hands-on inspection of the physical condition of the bridge. 

  • Castle Creek Bridge Inspection- Traffic adjustments will be in place during the day from November 28 to December 1, 2023. The project aims to work around peak traffic during the inspection. All vehicles must yield to flaggers at Sixth and Main Street during the project.
    • Traffic will be reduced to one lane on the bridge on Nov. 28-Dec. 1 from 8:30 a.m. and 2:30 p.m.  
    • Non-transit outbound traffic will be rerouted on to Power Plant Road. 
    • Public transit will be prioritized outbound. Flaggers will hold traffic to allow outbound buses to use the Castle Creek Bridge.
    • Possible night work - depending on weather - will take place 7:30 p.m. to 2:30 a.m.
  • Timeline: Jacobs in early summer 2024 will provide the city with a report regarding the feasibility of replacement of the existing bridge in its current location, including a proposed schedule and cost for accelerated construction and three-lane bridge construction, in addition to other work to answer community questions that arose during a 70-day community awareness effort regarding the history of the Entrance to Aspen.
  • Project Scope: The contract scope also includes a pre-National Environmental Policy Act (NEPA) Process Outline, including procedural paths forward considering cost, schedule and risks. The federal NEPA rules require an Environmental Impact Statement if a proposed major federal action is determined to significantly affect the quality of the human environment. Any of the 43 alternatives that were initially studied for the Entrance to Aspen in the 1990s but were screened out before resource impacts were fully analyzed during the EIS would require a new federal process/EIS.

Current Bridge Status

The Castle Creek Bridge was built in 1961 with an estimated lifespan of 75 years - expiring in 2036. It was rated “fair” by CDOT in 2022 (50.3 out of 100). If the bridge falls below a fair rating (below 50), CDOT could put weight limits on vehicles crossing the bridge in order to protect the safety of our community.

Get Up to Speed 

This 5-minute video runs through the history of the Entrance to Aspen to the present day. Learn more about the journey Aspen has taken through the lifetime of this project and where we're headed. To keep informed about the project, subscribe to receive email updates.

Questions? Email us.Click here to watch a short video about the New Castle Creek Bridge project. Opens in new window

Click here for more information about the history of the Entrance to Aspen
Click here for more information about the Preferred Alternative
Click here for more information about upcoming events

Constraints of the S-Curves

The S-Curves have a long history. In 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 community has experienced a bottleneck at the S-Curves. This creates limitations including: 

  • Only 700-800 cars per hour can navigate through the S-Curves due to their shape and size.
  • The current traffic alignment and travel patterns impact neighborhoods.
  • Trackless trams, light rail, or other new technology can’t be implemented due to lack of space.
  • Current backups out of town push vehicle traffic into the West End neighborhood causing safety issues and disruptions for residents.

The Path Forward - Two Choices

Because the Castle Creek Bridge’s lifespan only goes through 2036, we must start the 8-12 year bridge planning and implementation process now. There are currently two options for how to move forward. 

1: Castle Creek Bridge Remains the Primary Entrance & Exit 

  • Requires more frequent repairs, and vehicle weight limits will impact commercial deliveries as the bridge further deteriorates.
  • When more drastic repairs are needed, CDOT and FHWA are looking to Aspen’s City Council for support of the Preferred Alternative so that the New Castle Creek Bridge can be constructed. CDOT and FHWA will determine the best option to move forward to ensure the safety
  • Power Plant Road will need to be widened and realigned so that it can serve as a detour during extensive repairs or reconstruction of the old bridge. This process can take 18 to 24 months.
  • The rebuilt bridge will remain two lanes due to the existing bridge infrastructure such as the piers and foundation that hold up the bridge.

2. Build the Preferred Alternative

  • CDOT and FHWA are looking to Aspen’s City Council for support of the Preferred Alternative so that the new Castle Creek Bridge can be constructed.
  • The Record of Decision will undergo a standard reevaluation process.
  • CDOT, FHWA, and the City of Aspen will engage the community around design details (ex., pedestrian infrastructure and access), aesthetics, and open space planning (ex., land bridge design).
  • Voters approved the use of a two-lane parkway and light rail. Another vote is needed to allow bus lanes until funding is available for light rail.
  • 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.
  1. What are the challenges of rebuilding the existing Castle Creek Bridge?
  2. If we proceed with the Preferred Alternative, what’s next?
  3. What are the cost estimates and funding sources for the Preferred Alternative?
  4. What would the impacts to the community be during the construction of the new bridge, land bridge(s), and new road?
  5. Why can’t one of the other alternatives be considered instead of the Preferred Alternative?
  6. Can we build a tunnel so that we maintain the open space and trail connections?
  7. Can we proceed with a light rail now?
  8. How much does light rail cost?
  9. Would the connection to Cemetery Lane remain?
  10. Why is it important to Aspen residents to have a second bridge to get in and out of Aspen?
  11. Is the current Castle Creek Bridge safe?
  12. Have other bridges in our community ever had weight restrictions?
  13. When was the Castle Creek Bridge last inspected? What is the condition of the current Castle Creek Bridge and when will it be inspected next?
  14. Can the current Castle Creek Bridge be repaired?
  15. If Castle Creek Bridge needs to be repaired or replaced in the same location, what is the expected duration of that project?
  16. If the Preferred Alternative is built, will the old Castle Creek Bridge be transferred to the City of Aspen?
  17. What is a Record of Decision (ROD)?
  18. Why do we have to talk about this now? Life was just starting to get back to normal!
  19. What would the impacts to the community be during the construction of a new bridge, land bridge(s), and new road?
  20. How much will building the entire Preferred Alternative cost?
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