addressing climate change adaptation in regional transportation plans

Addressing Climate Change Adaptation in Regional Transportation PlansA Guide for California MPOs and RTPAscritical assets, it is necessary to consider a given strategy’s implementationfeasibility and effectiveness in the context of the risk it addresses.This process is thematically similar to the very quantitative and much more timeconsuming Benefit/Cost Analysis (BCA) process set out in the following section.Implementation feasibility is a broader means of expressing marginal cost (anaccounting of what it would take to implement the strategy above and beyondresources already or likely to be dedicated), and effectiveness modifies the riskproposition – potentially reducing the magnitude of the consequence, thelikelihood of occurrence, or both. Although not as precise (a debatable attribute)as a benefit-cost ratio, a qualitative determination that a given strategy addressesa high magnitude risk with a high degree of effectiveness and highimplementation feasibility (or, otherwise stated, low implementation barriers), isnonetheless useful in comparing the merits of adaptation strategies – aprerequisite for ranking them by priority.Benefit-Cost Based EvaluationThe Climate Change Adaptation and the Highway System (NCHRP 20-83(5))guidebook presents a climate risk adjusted Benefit-Cost Analysis (BCA)methodology as a means for “evaluating the cost-effectiveness of adaptationstrategies in meeting expected impacts, and the opportunity costs of notapplying the strategies.” This approach is sufficiently flexible for use in theCalifornia context, especially for agencies already employing BCA for projectselection. Due to its greater resource requirements, especially staff time andcapacity, the methodology is likely better applied to alternatives for a single assetor small selection of transportation assets.The framework structure incorporates several steps, which allow the user todevelop a benefit-cost ratio for a given strategy or strategies, weighted by thelikelihood of asset failure (a combination of the climate event probability and thelikelihood that the asset will withstand the event). In summary, the stepsinclude:1. Identify the most vulnerable infrastructure. This step encapsulates the assetselection process that unfolds in Module 3 and Module 4 of this document.NCHRP 20-83(5) includes a “diagnostic framework” that can also beemployed for this purpose.2. Estimate future operations and maintenance costs. This step requires theestimation of average annual operations and maintenance costs for twoscenarios: one with and one without adaptation.3. Estimate the agency costs of asset failure. This step requires estimation ofthe costs of asset failure. The definition of failure is intentionally vague, andshould be determined based on context.12-12 Cambridge Systematics, Inc.