SFEIS 4f Evaluation

Section 4(f) of the Department of Transportation Act of 1966 (Regulations at 23 CFR Part 774)

Section 4(f) was created when the United States Department of Transportation (USDOT) was formed in 1966. It was initially codified in Section 4(f) of the USDOT Act of 1966 which is where it got its name. Section 4(f) prohibits the use of publicly owned land of a public park, recreation area, or wildlife refuge of national, state, or local significance, or land of a historic site of national, state or local significance unless FHWA determines that there is no "feasible and prudent" avoidance alternative and that all possible planning to minimize harm has occurred. Section 4(f) only applies to actions of the US Department of Transportation (USDOT) and applies to Colorado Department of Transportation activities through federal funding or USDOT approval of transportation projects. In order for Section 4(f) to apply to a property, there must be a "use" of the property. A direct use occurs when land is permanently incorporated into a transportation facility or when there is a temporary occupancy of land that is adverse to a 4(f) resource.

Section 4(f) properties that are historic are identified through the Section 106 process. The portion of the Webb Ranch on the mesa top was determined a historic property and therefore was subject to evaluation under Section 4(f). Other historic Section 4(f) resources in the US 550 south connection area include numerous historic ranches, the Denver and Rio Grande Railroad and several historic ditches.

The first step in a Section 4(f) process is to identify the Section 4(f) properties and the alternatives that avoid them, and determine if they are feasible and/or prudent. Alternatives were evaluated for whether they met purpose and need as defined in the US 160 FEIS, safety and operational issues, social, economic, or environmental impacts, disruption to communities, construction, maintenance and operational costs, and any other unique problems or unusual factors.

Since it was determined that there are no prudent and/or feasible alternatives that avoid all Section 4(f) properties, a least harm analysis was prepared including all possible planning to minimize harm. The least overall harm is determined by balancing a number of factors such as how the impacts can be mitigated, how much the property will still be harmed even after mitigation, the views of the State Historic Preservation Office, the degree to which the alternative meets purpose and need for the project, the magnitude of impact to other environmental resources, and cost.

During the Supplemental Final EIS, the independent engineering firm helped with a preliminary assessment of the environmental impacts of the design variations being studied (alternatives proposed by the Webb Ranch and Revised G Modified 6 (RGM6), now the Preferred Alternative.  These have been included in the Revised Section 4(f) Analysis.

For more information about Section 4(f), please see

Click here to view the Section 4(f) Documents for the US 550 at US 160 South Connection SFEIS.

Project Contact:

Lisa Schwantes
CDOT Communications Manager
Region 5
[email protected]

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