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Case Law Updates on the Environment (CLUE)

Case Law Update Details

Case Title

Highlands Ranch Neighborhood Coalition v. Cater

Case No.

No. 1:16-cv-01089-RM

Court

U.S. District Court - Colorado

State

Colorado

Date

11/26/2018

Project

C-470

Project Type

Highway

Project Description

The project involved a 13.75-mile expansion of Colorado State Highway C-470 near Highlands Ranch. The Colorado DOT (CDOT) prepared an EA for the project. To validate the traffic noise model in the EA, CDOT collected short-term noise measurements at 15 locations along the C-470 corridor, along with the traffic counts, vehicle type data, and average speeds. CDOT then used the noise model to predict worst-hour noise levels for the existing roadway and the proposed expansion. CDOT used these predictions to determine areas to construct noise barriers to mitigate traffic noise impacts. Comments on the EA argued that CDOT should have collected long-term (24-hour) noise measurements to validate the traffic noise model. In response, CDOT collected long-term noise measurements at two locations along the C-470 corridor, along with traffic counts, vehicle type data, and average speeds. CDOT used this additional long-term data to determine that its noise analysis remained valid. FHWA then issued a FONSI for the project.

Case Summary

The plaintiff, an organization representing residents and property owners near the project, alleged that CDOT and FHWA violated NEPA by failing to properly validate the traffic noise model. In November 2017, the court ruled that the agencies violated NEPA by failing to document the rationale for their decision to use only short-term noise measurements to validate the traffic noise model. In response to the court’s order, in March 2018, CDOT and FHWA issued a 15-page Reevaluation that further explained the EA’s noise analysis and methodology. The court ruled that the Reevaluation did not satisfy its November 2017 order, and again remanded to the agencies.

Key Holdings

Compliance with Court’s Prior Order

The court ruled that the Reevaluation did not satisfy its prior order.

First, the court noted that the Reevaluation relied in part on FHWA’s 2011 Highway Traffic Noise Guidance, even though the agencies had previously argued during the litigation that the 2011 Guidance was voluntary and did not set requirements for the agencies. “[S]uch reliance is unexplained, i.e., why is the 2011 Guidance immaterial for one aspect of the noise analysis but of significant importance in another aspect?”

Second, the court faulted the Reevaluation for stating—without further explanation—that the agencies’ noise analysts did not believe that more data collection would be any more accurate than the agencies’ chosen methodology for validating the traffic noise model. “Defendants fail to provide any evidence or articulate any rationale to support their belief that the collection of long-term noise data would not provide any more accurate information.”

Third, the court questioned the timing of the agencies’ decision to collect and use short-term noise measurements. The court noted that the agencies’ chosen methodology for validating the traffic noise model (which used only short-term noise measurements) did not exist until two years after the agencies decided to only collect short-term noise measurements. Thus, the court concluded, the agencies’ stated justification for their decision to collect and use short-term noise measurements based on their chosen methodology was a “temporal impossibility.”

The court again remanded to the agencies. However, the court did not set aside the FONSI and allowed construction to continue in the interim. The court explained that the plaintiffs did not challenge construction of the C-470 project, and building additional noise barriers—the only relief sought by the plaintiffs—could be accomplished after construction of the highway lanes had begun. 

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AASHTO (American Association of State Highway and Transportation Officials)
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