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From page 12... ... 12 2.1 The NCHRP Project 08-91 Framework The NCHRP Project 08-91 framework was developed following an extensive review of theoretical and practical approaches to cross-asset resource allocation. As previously noted, the theoretical best practices confirmed the technical approach provided in the baseline framework; however, the state-of-the-practice review revealed that there are significant implementation challenges that must be addressed in order to successfully apply the theory amidst operational, political, and organizational considerations. Read the entire page →
From page 13... ... Research Guidebook 13 2.1.2 Performance Measures The framework incorporates performance measures (Step 2) as a means to track progress toward goal fulfillment with respect to system operations and asset conditions. Read the entire page →
From page 14... ... 14 Guide to Cross-Asset Resource Allocation and the Impact on Transportation System Performance associated with achieving mandated performance targets but can also allow for the agency to set targets based directly on agency goals and preferences. 2.1.3 Project Impact Assessment The application of performance models to forecast future performance with respect to various metrics is an essential component of the framework. Read the entire page →
From page 15... ... Research Guidebook 15 overlapping performance impacts not traditionally assessed within a silo (e.g., pavement resurfacing can lead to a safety benefit) Read the entire page →
From page 16... ... 16 Guide to Cross-Asset Resource Allocation and the Impact on Transportation System Performance is increasingly being applied at state DOTs. The challenge with this approach is that the allocation is reliant upon varying definitions of "need" and still takes a siloed focus instead of a system focus. Read the entire page →
From page 17... ... Research Guidebook 17 • Scale: Convert project benefits with respect to various performance metrics into dimensionless units that can be readily compared, • Score: Express project benefits in terms of their relative importance to the decision maker, • Prioritize: Divide project benefits by costs to determine feasibility and rank eligible projects, and • Optimize: Select the most cost-beneficial projects with respect to budget and performance constraints. The optimal cross-asset resource allocation is then equal to the ratio of the total selected project costs within each asset class divided by the total budget. Read the entire page →
From page 18... ... 18 Guide to Cross-Asset Resource Allocation and the Impact on Transportation System Performance Figure 8. Example top-down performance versus investment level trade-offs. Read the entire page →
From page 19... ... Research Guidebook 19 systems since each system typically considers different performance measures without consideration of cross-asset impacts. 2.1.5 Trade-off Analysis Trade-off analysis is applied in the framework to determine what performance can be bought given various investment scenarios and funding levels. Read the entire page →
From page 20... ... 20 Guide to Cross-Asset Resource Allocation and the Impact on Transportation System Performance with various hazard, financial, operational, and strategic threats and opportunities (Proctor and Varma, 2012) Read the entire page →
From page 21... ... Research Guidebook 21 By simulating distributions describing the likelihood of performance outcomes, practitioners identify the level of confidence in achieving performance goals. For instance, if the standard deviation for each project impact was known, the probability of various system performance measures could be determined (Figure 12) Read the entire page →
From page 22... ... 22 Guide to Cross-Asset Resource Allocation and the Impact on Transportation System Performance • Scale: Utility-based and linear scaling methods are programmed into the tool prototype. The utility method is preferred because it allows agencies to assign relative importance to varying levels of performance. Read the entire page →
From page 23... ... Research Guidebook 23 various summary graphics and dashboards are used to quickly view what performance can be achieved given user inputs. Additionally, as part of the MAP-21 legislation, state officials are asked to define various performance measures using system performance LOS and asset SGR. Read the entire page →
From page 24... ... 24 Guide to Cross-Asset Resource Allocation and the Impact on Transportation System Performance What could be done as a next step in the research would be to include the incorporation of windows of opportunity into the optimization for a long-range multiyear analysis period. For instance, if a bridge rehabilitation is not completed within sufficient time, then a bridge replacement might become the more prudent project. Read the entire page →
From page 25... ... Research Guidebook 25 (NHS) within an acceptable state of repair. Read the entire page →
From page 26... ... 26 Guide to Cross-Asset Resource Allocation and the Impact on Transportation System Performance Such a dashboard (e.g., Figure 13) can be customized per agency definitions of LOS and SGR. Read the entire page →

From page 12...

... 12 2.1 The NCHRP Project 08-91 Framework The NCHRP Project 08-91 framework was developed following an extensive review of theoretical and practical approaches to cross-asset resource allocation. As previously noted, the theoretical best practices confirmed the technical approach provided in the baseline framework; however, the state-of-the-practice review revealed that there are significant implementation challenges that must be addressed in order to successfully apply the theory amidst operational, political, and organizational considerations.