Cleveland National Forest Foundation et al. v. County of San Diego
(Cal. Ct App., March 27, 2025, No. D083555)
Introduction
The California Court of Appeal, Fourth Appellate District, has ruled that the County of San Diego’s adoption of two screening thresholds related to analysis of vehicle miles traveled (VMT) under the California Environmental Quality Act (CEQA) was not supported by substantial evidence. Specifically, the court held that the County’s Transportation Study Guide (TSG), which created exemptions from VMT analysis for certain projects, lacked substantial evidence and remanded the case with direction to determine whether other portions of the County’s TSG are severable and may continue to be applied. The decision underscores the obligation of lead agencies to support thresholds with localized, factual evidence demonstrating that exempted, or “screened out,” projects will not have significant environmental effects.
Factual Background
In 2013, the California Legislature passed Senate Bill 743 to shift CEQA’s method for evaluating transportation impacts away from traditional traffic delay metrics (e.g., level of service “LOS”) and toward VMT, measuring the amount and distance of automobile travel attributed to a project. In implementing this change, the Governor’s Office of Planning and Research (OPR) adopted revisions to the CEQA Guidelines and issued a Technical Advisory recommending specific VMT thresholds, including a 15 percent reduction benchmark and several screening criteria to identify projects unlikely to have significant impacts.
To implement these changes, the County of San Diego adopted its TSG, which included screening thresholds that exempted certain projects from detailed VMT analysis. At issue in the case were two of those screening thresholds: the infill threshold, which applied to projects proposed in designated infill village areas within the unincorporated county, and the small project threshold, which exempted projects expected to generate fewer than 110 automobile trips per day. The infill areas were designated based on housing and intersection density and job accessibility. The small project threshold mirrored OPR’s recommendation but was not based on any analysis specific to the County of San Diego.
Two environmental organizations filed a petition for writ of mandate challenging the County’s adoption of these screening thresholds, arguing that they lacked support in the administrative record and were inconsistent with CEQA. The trial court denied the petition, concluding that both thresholds were consistent with CEQA and supported by substantial evidence. Petitioners appealed.
Issues and Court’s Analysis
On appeal, the court considered whether the County’s screening thresholds complied with CEQA and whether substantial evidence supported the conclusion that projects falling within those categories would have less-than-significant VMT impacts.
The court rejected petitioners’ argument that CEQA mandates a quantitative threshold incorporating OPR’s 15 percent standard, explaining that CEQA permits agencies to adopt either qualitative or quantitative thresholds. However, the court emphasized that all thresholds, regardless of form, must be supported by substantial evidence showing that projects meeting the threshold criteria will not ordinarily result in significant impacts.
Turning to the two challenged screening thresholds, the court found that the County’s infill threshold lacked the necessary evidentiary support under CEQA. While the County assumed that infill development would generally result in lower VMT impacts, the court explained that assumptions alone are not enough. Citing its earlier Golden Door Properties, LLC v. County of San Diego (2018) 27 Cal.App.5th 892 decision, the court emphasized that agencies must show with evidence why a threshold makes sense for local conditions. In the words of the court, “the County was required to make some showing that development consistent with the adopted infill threshold will normally or likely result in an insignificant transportation effect.”
Here, the County did not base its infill threshold on actual VMT data, but rather “the general assumption that development in more dense areas, including infill development, does not significantly impact VMT.” The court was not persuaded by this premise and cautioned the County that it “is not enough to say that infill development is better than non-infill development.” The court also referred to the County’s own consultant-prepared maps showing that many of the designated infill and village areas had VMT levels at or above the County average. This record evidence directly contradicted the idea that development in those areas would have less-than-significant impacts.
In an effort to defend its approach, the County underscored its reliance on the California Air Pollution Control Officers Association’s Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and Advancing Health and Equity (CAPCOA Handbook) as a source of substantial evidence. But, the court noted that the CAPCOA Handbook does not define infill the same way and, therefore, “is not helpful.”
Similarly, with respect to the small project threshold, although the County had adopted the 110 daily vehicle trip limit directly from OPR’s Technical Advisory, it did so without evaluating whether that limit was appropriate in the context of San Diego County. CEQA permits agencies to adopt another agency’s threshold only if it is supported by substantial evidence. In this case, the court found the County made no effort to determine whether projects generating fewer than 110 daily trips would in fact produce less-than-significant transportation impacts under local conditions. Because the County failed to show some analysis to justify applying statewide guidance to local projects, the court ruled that the threshold could not be upheld.
Conclusion
This decision is yet another that underscores the necessity of developing thresholds of significance that are supported by geographically tailored, local information and data. General suppositions and rules of thumb, even when conceptually endorsed by state agencies, will not suffice absent evidence affirming that their local application will, in fact, achieve the desired result – in this case, a less-than-significant VMT impact.
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