1.2. National Performance Measure for Roadways:
As noted in the draft strategic plan, Moving Ahead for Progress in the 21st Century (MAP-21) requires States to develop and implement asset management plans and performance plans specifically for roadways and bridge infrastructure. ACPA believes that States can address these provisions for pavements by using a concept called Remaining Service Life (RSL). RSL is the anticipated time until the next required rehabilitation of a pavement section. It is useful as a Performance Measure because it augments pavement condition data by also considering pavement deterioration information. RSL is useful as part of an Asset Management Plan as well, because it can help ensure that investments are made to improve the life and usability of the highway system. Finally, RSL is also effective in the Planning Process as it allows agencies to predict, with reasonable accuracy, the long-term costs of future maintenance and rehabilitation activities.
Currently, IRI is being debated as the National Performance Measure. However, there are some significant concerns with using it as such. First, IRI only measures the functional condition (ride) of the pavement. To have a clear understanding of how well a pavement is serving the public, both functional and structural conditions of the pavement need to be taken into account. Second, IRI (as well as structural conditional data such as cracking, rutting, and faulting) only provide a measure of the current condition of the pavement network. They do not provide information on what future conditions will likely be.
RSL is a better National Measure of the current condition of pavement networks because it adds a “time” element to how well a pavement network is serving the public (a pavement with a higher RSL is serving the public longer and is therefore serving the public better). RSL is also the basis for “risk-based” and “performance-based” programs because it provides insight into how the pavement network will perform for the next 10 to 20 years, as well as what is required from pavement investment strategies to maintain the system. Additional advantages of RSL include:
• It is a multi-conditional measure and can be developed from any type of functional and / or structural data.
• It is flexible and allows State DOT’s to use their current Pavement Management Data and to develop individual condition targets to meet the National Goals.
• It can forecast future pavement performance with sufficient accuracy to plan future maintenance and rehabilitation needs.
• It can be used to compare different scenarios to determine what are the best investment strategies to ensure sustained performance over any time horizon.
• It can be used to show the impact of different funding levels and helps determine the best long-term funding strategy to ensure sustained performance.