Guidelines For Informing Decisionmaking To Affect Pavement Performance Measures

The Federal Highway Administration (FHWA) issued a Notice of Proposed Rulemaking to establish performance measures for the Interstate Highway System (IHS) and the National Highway System (NHS) to assess the condition of the pavement on the IHS and NHS. The performance measures, as proposed by FHWA, to assess the condition of the pavement are based on the percentage of pavements on both the IHS and NHS (excluding the IHS) in good and poor condition. The condition of the pavements is to be determined based on the following metrics: International Roughness Index, cracking percent, rutting, and faulting. The overall objective of the research study that led to the guidelines contained in this report was to validate the proposed pavement performance measures and to demonstrate their use within asset management; this validation study is documented in a companion report. Guidelines for informing decisionmaking to affect pavement performance measures were developed based on the findings from the validation study. The goal of the guidelines is to illustrate to agencies potential strategies to move the overall condition from poor to fair to good. In meeting this goal, the guidelines will enable highway agencies to address critical questions such as the following: What are the drivers of the performance measures? What are the effects of maintenance and rehabilitation treatments on condition metrics and overall condition?

Federal Highway Administration (FHWA) issued a Notice of Proposed Rulemaking to establish performance measures for the Interstate Highway System (IHS) and the National Highway System (NHS) to assess the condition of the pavement on the IHS and NHS.(1) The performance measures, as proposed by FHWA, to assess the condition of the pavement are based on the percentage of pavements on both the IHS and NHS (excluding the IHS) in good and poor condition. The condition of the pavements is to be determined based on the following metrics: International Roughness Index, cracking percent, rutting, and faulting. The overall objective of the study was to validate the proposed pavement performance measures and demonstrate their use within asset management. Performance and distress data from the Long-Term Pavement Performance database were translated into the pavement condition metrics used by the performance measure proposed by FHWA. The performance measure validation considered review of the performance measures over time to determine if they followed a logical trend; comparison of performance measures against maintenance and rehabilitation (M&R) activities to demonstrate if the performance measures are impacted by M&R activities; and review of the performance measures against thresholds for logic and reproducibility, temporal analysis, effects of alternate thresholds, and identification of performance measure drivers. Standalone guidelines for informing decisionmaking to affect pavement performance measures were also developed based on the study findings; they are provided in a companion report.

The results of this validation study showed that the performance measures are comprehensive with respect to the state of the practice--they address functional and structural (albeit using cracking as a surrogate) performance. They are balanced as they comprise several individual types of metrics (IRI, cracking, rutting, and faulting), and they show the expected performance trend over time. A parallel study detailed in the FHWA Interstate Pavement Condition Sampling report addresses these and other criteria, including appropriateness or measures at the national level. Although improvements are possible, the performance measures are considered appropriate and valid for their intended purposes.

Abstract : As the infrastructure industry moves towards adopting Environmental Product Declarations (EPDs), as instruments for communicating the environmental impacts from pavements, there is a growing need to develop methods that support the informed use of mid-point impact indicators such as Global Warming Potential (GWP) in the design decision-making process. This research presents an equivalent solutions framework that will aid decision-makers to inform the design of pavement systems by explicitly accounting for performance requirements, costs and mid-point environmental impact indicators as reported through instruments such as EPDs. A limited illustration of the framework is provided for the case of Hot-Mix Asphalt (HMA) mixtures containing Reclaimed Asphalt Pavement (RAP). A trade-off between each distress and GWP are identified through Lagrange multipliers. The outcomes of the analysis provide decision-makers with guidelines on margins of tolerance and indicate the possibility of identifying equivalent functionalities (for GWP and TC) across designs with varying RAP content.

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 424: Engineering Economic Analysis Practices for Highway Investment explores how U.S. transportation agencies have applied engineering economics--benefit–cost analyses and similar procedures--to decisions on highway investments.