addressing climate change adaptation in regional transportation plans

Addressing Climate Change Adaptation in Regional Transportation PlansA Guide for California MPOs and RTPAsAlthough there are no strict requirements, generally boundaries can be definedusing the following guidelines:Regional. Including the entire MPO or RTPA geography may provide themost comprehensive geographic coverage, but may necessitate sacrifices inthe quantity, type, and scale of data used to populate the inventory. Forexample, lower roadway functional classifications, such as local access roads,might be omitted or suppressed in order to shift resources to more criticalroadways, such as freeways and other principal arterials. Corridor. Corridors can be oriented to the transportation system(representing a thick backbone of roadway or multimodal infrastructure, forinstance), or emphasize economic, social, or natural features. A corridor canbegin and terminate within a single region, or run through multiple regions.The choice of corridor boundaries will depend on the objectives of the overallassessment and, again, on the desired scale of the analysis.Political Unit. At the level of the county or municipality, the granularity ofdata may be finer and more directly relevant to study objectives (bicycle andpedestrian oriented infrastructure, for example, become more readilyaccessible at reduced scales). However, smaller geographic analyses maytrade a more comprehensive perspective (of network dependencies, forexample) for the ability to focus more closely on a more narrow physical area.Modal. If the study objectives focus on a single or small subset of modes, itmay be appropriate to constrain the study boundary only to geographiesrelevant to that mode or modes. A study focused on general aviationairports, for example, may lead to a study area comprised of severalgeographic “islands” – although expanding the study to assess airport accesswould require the addition of a selection of roadway layers.The choice of asset types to be included will have a significant impact on theresources required for the assessment (with the exception of the “Modal”method, of course). A very extensive geography may be manageable if a limited,standardized selection of assets is included (Interstates, for instance), whereas asmall geography richly layered with modal infrastructure and other asset typesmay be very labor intensive.Define Asset CategoriesConsider the Universe of Asset TypesAlthough the types and overall quantity of assets eventually included in the assetinventory will likely comprise only a small selection of the overall universe(within the study boundaries), it is good practice to devote some time up front todefining that universe. This step can lead to the identification of synergies oropportunities that involve little marginal effort (“if we’re collecting this, why notthat as well?”); and also help prevent obvious omissions. For highlyCambridge Systematics, Inc. 9-3