Research has shown that incorporating pavement structural condition along with pavement surface condition in a pavement management decision-making process leads to better-informed decisions, and more cost-effective pavement rehabilitation and preservation strategies. Recognizing this, some highway agencies have investigated the use of Falling Weight Deflectometer (FWD) for pavement management applications. While FWDs are a common device for project level structural evaluation, they are inefficient at the network level. FWD measurements are made at discrete points along the pavement sections and the equipment has to remain stationary on the road during each testing point (typically 1-4 minutes, depending on the protocol). This requires lane closures that disrupt traffic and traffic control, which limits the productivity and the number of discrete points where measurements can be obtained. Over the last 15 years, traffic speed deflection devices (TSDDs) that can near-continuously measure pavement structural condition while traveling at traffic speed have been developed. The Greenwood Engineering TSD (Traffic Speed Deflectometer) and the ARA RWD (Rolling Wheel Deflectometer) are two such devices that were discussed by the SHRP2 R-06(F) project “Assessment of Continuous Deflection Measuring Technologies” and thoroughly evaluated in a recently completed FHWA project “Pavement Structural Evaluation at the Network Level.” More recently, Dynatest has also developed a new device named RAPTOR (Rapid Pavement Tester®). Demonstration of TSDDs in the US and around the world have highlighted their benefits in providing valuable information about the pavement structural condition. However, to effectively implement TSDDs and incorporate TSDD data in pavement management decision-making, highway agencies need guidance on (1) data collection protocols, (2) data interpretation guidelines for network and project level applications, and (3) developing a framework to implement continuous deflection measurements as part of the agency’s pavement management system (PMS).

The objective of the proposed pooled-fund project is to establish a research consortium focused on providing participating agencies guidelines on how to specify collection and use data collected with TSDDs for network- and project-level (if feasible) pavement management applications. Specific tasks within this multi-year program will be developed in cooperation with the consortium participants. In addition, the consortium will also provide participating agencies with a mechanism to conduct pilot demonstration testing in their respective networks.

The work plan will be developed based on the priorities indicted by the consortium participants, during the kick-off meeting. It is anticipated that the details and scope of the objectives will be further defined to reflect the concerns of the consortium participants. However, it is proposed that the project will include the following tasks: (i) Develop a list of available devices and their characteristics. This will include details about the number of devices currently in operation and what type of data they collect. (ii) Develop data collection guidelines and specifications for agencies. This will include reviewing best practices from around the world and will be coordinated with service providers to ensure proposed guidelines can be implemented. (iii) Develop guidelines on how to incorporate pavement structural condition data into agency network-level pavement business processes. This will include defining what structural indices to use, and investigating how the structural condition data can complement currently collected surface condition data to make better decisions. (iv) Demonstrate how structural condition collected from TSDDs can be used for supporting project level decision-making based on case studies. (v) Demonstrate the costs effectiveness of collecting structural condition data both, at the network and project levels, through case studies. (vi) Collect data on at least 100 miles of interstate or primary type pavements for each year of participation with the option to include additional testing at additional commitment levels. (vii) Organize and deliver workshops and training material for the consortium members. The pooled-fund project will be led by the Virginia Department of Transportation (VDOT) through its research office, the Virginia Transportation Research Council (VTRC).

This project is expected to have a minimum participation of at least five agency members (including FHWA). Each agency member can participate at one of the following options: Option 1) Participation in pooled fund study and travel costs for one representative of the participating agency, or their designee, to attend annual face-to-face Technical Advisory Committee (TAC) meetings = $15,000 per year. Option 2a) Option 1 plus one day of TSDD testing on agency designated routes (approximately 100-200 miles depending on routes selected) = $55,000 per year. Option 2b) Option 2a plus additional days of TSDD testing on agency designated routes (approximately 100-200 miles per day depending on routes selected) = $47,000 per day per year. The consortium will be initially set for three years, with possible continuation depending on the needs of the participants. A waiver has been requested for 100% SP&R Approval.