Overview
Transportation agencies are frequently challenged by budget constraints to maintain roadway pavements and other infrastructure in good condition. As a result, it is critical that transportation infrastructure investments are costeffective and results-oriented. Performance-based Planning and Programming (PBPP) is the application of performance management principles within the planning and programming processes of transportation agencies to achieve desired performance outcomes for a multimodal transportation system. Transportation Asset Management (TAM) is strategic and systematic process of operating, maintaining, upgrading, and expanding physical assets effectively through their life cycle, and is ideally adopted within a broad PBPP framework. For many, if not all, transportation agencies, highway pavements are the most valuable asset that they manage. Thus, performance (life-cycle) management of pavements is a critical component of a TAM system.
Within pavement performance management, four primary metrics of pavement condition are used: structural-adequacy/deflection, surface distress, serviceability (smoothness), and surface friction. The most commonly collected of these primary metrics are those that are required for federal reporting. Under the National Highway Performance Program (NHPP) introduced in the 2012 federal transportation funding bill (MAP-21) and adopted by the 2015 FAST Act, states and are required to report surface distress metrics of cracking, rutting, and faulting, as well as serviceability (in the form of the International Roughness Index [IRI]). Dozens of other primary and secondary metrics also can provide additional value.
The Michigan Department of Transportation (MDOT) has historically operated a pavement management system based on a department-created ‘distress index’ (DI), which is then used to estimate the pavement’s remaining service life (RSL). MDOT also uses a pavement rating scale (PASER) via ‘windshield survey’ to assess road conditions for the entire statewide system.
Under emerging federal regulations, MDOT will be required to adopted specific PBPP practices including the development and use of a risk-based Transportation Asset Management Plan (TAMP) for the statewide National Highway System (NHS). The TAMP will be required to address metrics and targets established by the NHPP, and thus will require MDOT to amend established TAM practices.
Federal NHPP requirements set minimum standards for pavement performance management, but states are encouraged to incorporate additional metrics on pavement and other infrastructure assets in the state TAMP. Advancing technologies may allow for the creation of novel metrics and collection techniques that could expand the scope of Michigan’s TAMP and facilitate more cost-efficient outcomes in all aspects of TAM. Technology advances that could be integrated into a TAM program include:
- Smartphone apps and crowdsourcing
- Automated vehicle systems data
- In situ structural health monitoring
- Automated distress classification
Regardless of what data are collected, a transportation asset management program must be appropriately designed to be capable of translating raw data into useful, actionable information. Currently, the state-of-the-practice in pavement design and performance management is a mechanistic-empirical (M-E) approach favored by the American Association of State Highway and Transportation Officials (AASHTO) and Federal Highway Administration (FHWA). AASHTO published the Mechanistic-Empirical Pavement Design Guide (MEPDG) in 2008 with associated design software. MDOT adopted the MEPDG for pavement design in 2015. Fully utilizing improved pavement design approaches and novel data types will require expanding the use of coherent PBPP frameworks across the organization.
Further information regarding performance-based transportation asset management and pavement performance management is available from the FHWA Asset Management Program Office at http://www.fhwa.dot.gov/asset/, and the AASHTO TAM Portal at http://www.tam-portal.com/.