BACKGROUND: Imaging systems are commonly used for conducting pavement evaluations. AASHTO Standard Practice for Collecting Images of Pavement Surfaces for Distress Detection (AASHTO Designation: PP 68) addresses the collection of images. However, there are no widely accepted methods for measuring the characteristics of pavement surface images (such as 2-dimensional optical images and 3-dimensional surface elevation images). There are also no widely accepted AASHTO standard practices for the calibration, certification, and verification of such images. Research is needed to identify the characteristics of surface images that are essential for pavement evaluation and develop methods for measuring these characteristics, and also to develop recommended standard practices for implementing these methods. This information will help highway agencies better evaluate image data collection systems and improve the process of pavement condition evaluation.
OBJECTIVES: The objectives of this research are to (1) identify and develop methods for measuring the characteristics of surface images used for pavement evaluation and analysis; and (2) develop recommended standard practices for the calibration, certification, and verification of such images, for consideration and adoption by AASHTO.
Phase I: (1) Collect and review relevant domestic and foreign literature, research findings, and information relative to image-based surface estimation for pavements and other applications. This information may be obtained from published and unpublished reports, and contacts with public and private organizations involved in the collection and analysis of such image Information relevant to this research may be available from Pooled Fund Study TPF-5(299), Improving the Quality of Pavement Surface Distress and Transverse Profile Data Collection and Analysis (https://collaboration.fhwa.dot.gov/dot/fhwa/tpf5299/default.aspx) and NCHRP Project 01-57A, Developing Standard Definitions for Comparable Pavement Cracking Data (https://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=4276) by contacting the responsible individuals noted on the websites). (2) Based on the review performed in Task 1, identify the characteristics of surface images relevant to pavement evaluation and analysis and assess their importance. Identify those quality characteristics that are essential for pavement evaluation and recommend characteristics for further investigation in Phase II. (3) Based on the evaluations performed in Task 2, prepare an updated, detailed work plan for Phase II that includes an approach for assessing the identified essential quality characteristics, and identifying/developing validated methods for measuring them. (4) Prepare Interim Report 1 that documents the research performed in Tasks 1 through 3. Following review of the interim report by the NCHRP, the research team will be required to make a presentation to the project panel. Work on Phase II of the project will not begin until the interim report is approved and the Phase II work plan is authorized by the NCHRP. The decision on proceeding with Phase II will be based on the contractor’s documented justification of the updated work plan.
Phase II: (5) Execute the Phase II plan approved in Task 4, and identify/develop validated methods for measuring the quality characteristics of surface images. For these methods, prepare proposed standard practices and/or methods of test in AASHTO format. (6) Using the methods identified/developed in Task 5, prepare an updated, detailed work plan for Phase III that includes an approach for developing and validating standard practices for calibration, certification, and verification of pavement image data collection systems. (7) Prepare Interim Report 2 that documents the research plan proposed in Task 6. Following review of the interim report by the NCHRP, the research team will be required to make a presentation to the project panel. Work on Phase III of the project will not begin until the interim report is approved and the Phase III work plan is authorized by the NCHRP. The decision on proceeding with Phase III will be based on the contractor’s documented justification of the updated work plan.
Phase III: (8) Execute the plan approved in Task 7, and develop the proposed standard practices, in AASHTO format. (9) Identify issues affecting implementation of the proposed methods and standard practices developed in Tasks 5 and 8, respectively (e.g., costs and benefits, need for new data elements, new equipment, and increased effort), and propose possible actions to address these issues. (10) Prepare a final deliverable that documents the entire research effort. The recommended standard practices and/or methods of test shall be prepared as stand-alone documents.
TATUS: Research in Progress.