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40 · Useful for Decision Support--The measure should pro- Following development of the initial set of measures, a proj- vide information that helps support the decision-making ect workshop was held to review all aspects of the project. This process. It should be collected frequently enough and workshop was held in Dallas, Texas in March 2008. Partici- demonstrate changes clearly enough to reflect impacts of pants included representatives from FHWA, state DOTs, and agency actions. Ideally, it should be possible to distinguish the private sector, as well as the Project Panel. Based on com- between changes in the measure resulting from actions ments received from workshop participants and panel mem- under an agency's control and external drivers. bers, the research team revised the initial set of performance · Useful Across the Organization and Beyond--The mea- measures and developed the recommended set presented in sure should be easily understood and communicated within Section 5.3. Further, the research team distinguished between an organization and to external stakeholders. The measure core measures that in theory any IHS owner should be capable should function as part of a family of measures that can be of capturing and should appear in any Interstate Asset Man- used to describe performance at different levels of aggrega- agement Plan and additional comprehensive measures. Ideally, tion (e.g., corridor, state, entire IHS system), different time every IHS owner would report the core measures described horizons, and for different audiences. here, at a minimum, and plan in the future for collecting and reporting the full set of comprehensive measures. Step 4--Apply Selection Criteria 5.3 Recommended Measures for IHS In this step, criteria were applied to the set of measures com- Asset Management piled previously, including measures identified in Step 1 and additional measures for which a need was identified through Table 5.1 details the core set of performance measures rec- the gap analysis performed in Step 2. The result of this step was ommended for the Interstate Asset Management Framework. an evaluation of each of the measures on the basis of the crite- Performance measures are organized by category. For each cat- ria described above. egory, the table lists the asset type, where applicable, as well as After an initial attempt to classify individual measures for the measure type and measure. Table 5.2 lists additional, com- each criterion on a high/medium/low scale, the research team prehensive measures. found that a more useful approach was to group like measures Note that the measures are intended to characterize overall (e.g., by category and asset), and characterize the variation conditions of the portion of the IHS managed by a given orga- nization, rather than a specific section or the overall transporta- between members of the group descriptively. For instance, for tion network. Additional detailed data are required in every bridge preservation measures, there are many possible mea- category for making project-level and operational decisions, sures of bridge condition, most derived from NBI and/or such as for determining appropriate treatments at the asset element-level data described in Chapter 4. Generally speaking, level. Additional high-level measures may be useful for evalu- the detailed measures derived from the available bridge data ating the overall state of the transportation network. The fol- that are most useful for decision support (e.g., element-level lowing paragraphs discuss each category. conditions) are least useful for communication across and out- side an organization, and most likely to require additional data Preservation. This category includes measures of asset that may or may not be available consistently from one agency condition for each asset type. For pavements, two measures to another. Thus, these measures are best considered as a are recommended: structural adequacy and ride quality. PSR group, weighing the relative advantages and disadvantages of can be used to approximate structural adequacy. However, each of the alternative measures compared to the others. most agencies have established agency-specific measures that consider rutting, cracking, and faulting. Pending update of the Step 5--Finalize Set of Measures HPMS, these agency-specific measures are preferable to PSR. For characterizing bridge conditions, the percent of bridges The last step of the process was to finalize the set of perfor- classified as structurally deficient (SD) is recommended as the mance measures recommended for the Interstate Asset Man- best overall measure available for supporting IHS asset man- agement Framework. The research team developed an initial set agement. Note that the determination of whether or not a of recommendations that addressed all of the assets on the IHS bridge is functionally obsolete (FO) is not recommended as a and each of the categories identified previously. Where multi- measure of bridge condition, as this measure specifies whether ple measures were available for characterizing a given asset or the bridge is designed to current functional standards rather objective, the research team relied upon the results of Step 4, than characterizing its physical condition. Thus, a bridge could supplemented with best practice examples, to pare down the be classified as FO but not have any preservation needs. list to keep it as short as possible while still providing compre- The recommended pavement and bridge measures are hensive coverage. tracked and can be predicted using agency pavement and
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41 Table 5.1. Recommended core performance measures for the Interstate Asset Management Framework. Category Asset Type Measure Type Measure Preservation Pavement Structural Adequacy Present Serviceability Rating (PSR) or an agency's pavement condition index Ride Quality International Roughness Index (IRI) Bridges Structural Deficiency Percent classified as Structurally Deficient (SD), weighted by deck area Signs Asset Performance Percent functioning as intended Pavement Markings/ Asset Performance Percent functioning as intended Delineators Guardrails Asset Performance Percent functioning as intended Mobility Travel Time Travel time index Delay Delay per vehicle in hours Safety Crash Rate Number of crashes expressed as number per year and per VMT Fatality Rate Number of fatalities expressed as number per year and per VMT Environment Agency-specific report Pass/fail indication for each measure card of environmental milestones bridge management systems, or alternatively using HERS-ST Mobility. This report recommends using travel time and NBIAS developed by FHWA. It is important to note that index (the ratio of actual travel rate to the ideal rate) and existing pavement and bridge management systems consider average delay as the best overall measures of mobility. Both multiple objectives and constraints in developing work recom- measures can be calculated from readily available HPMS data mendations, and use additional measures and criteria for rec- and predicted using HERS-ST, and can be reported by rural/ ommending work besides the measures listed in Table 5.1. The urban roads, by corridor, and/or separately for autos and recommended pavement and bridge measures are intended to trucks. Winter maintenance is included here as a compre- provide an overall indication of asset conditions, and not hensive measure in the mobility category, with a measure of intended for use as a tool for prioritizing work or a replacement average time to bare pavement following a snow event. In cold for pavement and bridge management systems. weather, states' winter maintenance is a core issue, but is gen- For other assets beside pavements and bridges, this report erally not managed by system. recommends calculation of the percent of the asset quantity "functioning as intended" as the measure that can best support Safety. Crash and fatality rates are recommended as the best overall measures of safety outcomes. Typically these are the Interstate Asset Management Framework. reported in terms of total numbers of crashes and fatalities, and An important issue in considering the measures in this cat- the rate reported as the number per 100 million VMT. egory is that of what measures should be considered core ver- sus comprehensive. In reality, all assets on the IHS are of great Environment. Rather than recommending a specific set of importance. However, the fact that all assets are important measures as in the other categories, this report recommends a does not necessarily mean that it is vital for an IHS owner to report card approach for the Environment category, whereby capture and report performance measures for all IHS assets in an IHS owner establishes a set of environmental milestones, the near term as part of its Interstate Asset Management Plan, and reports whether they are achieving them on a pass/fail possibly diverting resources from other important activities to basis. These milestones may include any of the examples listed do so. Further, it is assumed that IHS owners do now and will above, and should include an indication of whether or not the continue to address public safety issues (e.g., pending failure of IHS owner is satisfying its environmental commitments. a structure) even in the absence of an Interstate Asset Manage- ment Plan. Thus, the consideration of what assets are core ver- Other. Cost control and schedule adherence are rec- sus comprehensive was based primarily on consideration of ommended as comprehensive measures of project delivery. asset extent and degree to which data are available. Reporting delivery measures is becoming increasingly