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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

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Publication Number:  FHWA-HRT-13-050    Date:  November 2013
Publication Number: FHWA-HRT-13-050
Date: November 2013


Pavement Remaining Service Interval Implementation Guidelines



The basic process used to determine future pavement construction needs is illustrated in figure 1. Most pavement construction activity planning is based on an annual fiscal time cycle used by an agency. The steps shown in this figure are cyclical and depend on the time cycle appropriate to the type of pavement asset. The process starts with input data that are fed into the expectancy model to predict future changes in the construction trigger models. The outputs from the predictions are used to select the most appropriate construction strategy, which is used to develop construction plans and specifications. The feedback cycle starts with documentation of the actual condition observed over time as well as the actual construction activities performed. Monitoring measurements provide updated inputs for the next planning cycle and also refine expectancy models.

This figure shows a flowchart of the future pavement construction needs process. The flow chart consists of five boxes that each containing a different element of the process. The first box, which is located in the upper right corner of the figure, is labeled  Inputs.  An arrow extends from the bottom of the box downward and connects to the top of the second box labeled  Expectancy Models.  An arrow extends from the bottom of the box downward and connects to the third box labeled  Strategy Selection.  An arrow extends from the left of the third box upward (signifying a clockwise motion) and connects to the fourth box labeled  Construction.  An arrow extends from the top of the box upward and connects to the final box labeled  Monitoring.  An arrow extends from the box and connects back to the first box labeled  Inputs,  completing the flowchart
Figure 1. Flowchart. Future pavement construction needs process.

Within the context of the process illustrated in figure 1, the fundamental elements required to replace the existing RSL terminology with the new RSI terminology include the following:

The logic of this structure is based on separating the definitions of what future construction event is needed from how the need is determined.

Construction Event Terminology

The objective of construction event terminology is to uniquely define what type of predicted future construction event is needed. This vocabulary is needed to describe the construction treatments to promote database integration and increase levels of aggregation at local, district, State, and national levels. Moreover, the terminology requires the identification of three attributes: time when a treatment is needed, type of construction treatment, and reason for the construction treatment.

The time (or the year) when a treatment is needed is specified since this is the basis for budget planning. This is meant to replace prediction models based on traffic applications. Traffic application rates used in the modeling process need to be converted to a time basis. Converting traffic application rates to a time basis is a complex process based on considering the design lane (which receives the most truck loadings), multilane facilities, damaged lanes (which are the lanes in the worst condition), and other local factors that influence pavement damage from vehicle and environmental effects.

The following examples highlight definitions of construction events based on the expanded paradigm of common pavement improvements included in many pavement management systems (PMSs):

The definitions only describe what type of construction treatment is being applied to the pavement. An indication of the reason(s) why a future construction event is predicted is needed to complete the definition since pavement improvements are based on different needs. The following examples highlight controlled terminology that can be used to explain the basis of predicted time to a threshold event:

Typically, an agency will develop a decision matrix to use as part of its pavement management process. This matrix will associate types of pavement deficiencies requiring construction actions with types of construction best suited to correct them. For example, if the roughness exceeds the IRI threshold, then a typical approach would be placing an overlay to correct the roughness.


The framework for implementing the new RSI terminology is illustrated in figure 2. The key components of the framework that must be addressed by SHAs to develop, implement, maintain, and update a construction needs analysis methodology that includes generic agency and RSI implementation issues.

These components should be tailored to the individual agency requirements related to budgeting process, types of pavements in use, common types of pavement deficiencies requiring correction, construction contract instruments, and other considerations.

The generic agency issues address the establishment of the agency’s RSI protocol, the identification of an RSI coordinator, and the dissemination of the RSI concept within the agency. These issues only need to be addressed once, with periodic monitoring and revising to ensure they are still appropriate; however, they are vital to the success of an agency’s RSI program. These generic agency issues are discussed in more detailed in the appendix.

This figure shows a flowchart illustrating the framework for implementing the new remaining service interval (RSI) terminology. The figures contains four separate boxes that are stacked on top of each other in a column and are separated with downward arrows representing flow between the boxes. The top box is labeled  Generic Agency Issues.  The second box contains the following text:  (1) RSI protocol,(2) RSI coordinator, and (3) RSI dissemination.  The third box is labeled  RSI Implementation.  The final box contains the following text:  (1) Construction triggers, (2) threshold limits,(3) expectancy curves, (4) collection of inputs, (5) strategy selection, and (6) assessments and updates
Figure 2. Flowchart. Agency RSI implementation.

The RSI implementation issues focus on a step-by-step approach that is necessary to successfully establish the RSI concept within the agency. These RSI implementation steps are discussed in the following two chapters of this report.