In late January, the Governor’s Office of Planning and Research (OPR) released its revised proposal to update the CEQA Guidelines with respect to the analysis of transportation impacts. OPR has not backed off from the main thrust of its original proposal: abandonment of “level of service” (LOS) in favor of “vehicle miles travelled” (VMT) as the primary metric of significance. However, the revised proposal recognizes that implementation of this sea-change in one of the most complex (and heavily litigated) areas of impact analysis cannot happen overnight, and lead agencies and consultants will benefit from some technical assistance up front.

Currently, the most common metric used in evaluating a project’s transportation impacts is LOS, which measures the delay that vehicles experience at intersections and on roadway segments. However, as OPR noted in its original proposal, focusing on a project’s impact on LOS often has unintended consequences, including the imposition of mitigation measures – such as increased roadway capacity – that can exacerbate poor traffic conditions over the long term. It can also discourage infill development, because adding traffic to urban areas increases the likelihood of a finding of significance that would trigger the need for an environmental impact report (EIR).…