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.

Engage with us on this vital community project:

  1. Read the information below.
  2. Attend an event.
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Questions? Email us.

¿Hablas español? Comunícate con nosotros al 1-970-920-5080 para compartir información y materiales disponibles en español.

Get Up to Speed 

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

Project History

In the mid-nineties, hundreds of community members worked tirelessly to address traffic congestion and improve air quality through plans for a different Entrance to Aspen. This work was used by the Colorado Department of Transportation (CDOT) as the foundation to create 10 project objectives. These objectives are still being used today to make decisions about the Entrance to Aspen. To meet these objectives, CDOT and the Federal Highway Administration (FHWA) evaluated 43 different alignments and lane configurations, solicited public comment, held an official public hearing open house, and considered comments from 951 letters about what the future of the Entrance to Aspen could be. 

The Decision:

  • CDOT and FHWA selected one out of 43 alignments that met all 10 project objectives. This is known as the “Preferred Alternative”.
  • The Preferred Alternative and key transportation improvements between the airport and Aspen (such as the roundabout and the new Maroon Creek Bridge) are part of a larger document called the Record of Decision (ROD) that was finalized in 1998.
  • The ROD was specifically written to include flexibility, welcoming public input on future design elements that would meet community needs and desires. 
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A train crosses the original Castle Creek Bridge

The Preferred Alternative

The Preferred Alternative extends Main Street over a new Castle Creek Bridge and under a land bridge that meets the existing Highway 82 near the roundabout. 

A rendering of the Preferred Alternative as is meanders through Marolt-Thomas Open Space.

Details include: 

  • Two general-use lanes and two exclusive bus lanes that can accommodate light rail or trackless trams in the future. 
  • A bridge over Castle Creek along the new alignment. 
  • Increased transit capacity while decreasing transit time with continuous bus lanes from the roundabout to downtown.
  • The highway across the 82-acre Marolt-Thomas properties covers 5.4 acres, and 2.5 acres are gained from the land bridge and decommissioned Highway 82 between the roundabout and Cemetery Lane. 
  • The existing Castle Creek Bridge remains in use as a local connection to the Cemetery Lane neighborhood and McLain Flats.
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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.

Current Bridge Status

As mentioned above, 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 2020 (52 out of 100) and will be reevaluated again soon. 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.

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 will determine the best option to move forward to ensure the safety of the traveling public.
  • Power Plant Road will need to be widened and realigned so that it can serve as a detour during the repair 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 existing piers and foundation that holds 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 (Land bridge design). 
  • Aspen voters will need to approve the use of Marolt-Thomas Open Space for exclusive bus lanes.
  • The existing Castle Creek Bridge will be used while a new bridge is constructed.