The National Academies

NCHRP 20-50(20) [Active]

LTPP Data Analysis: Develop Practical Tools and Procedures to Improve WIM Data Quality

  Project Data
Funds: $350,000
Staff Responsibility: Camille Crichton-Sumners
Research Agency: Applied Research Associates
Principal Investigator: Dr. Olga Selezneva
Effective Date: 10/1/2018
Completion Date: 7/30/2019
Comments: Research in progress.



Weigh-in-motion (WIM) systems are a vital means for collecting traffic data—critical input for pavement and bridge designs—used for making transportation and freight planning decisions and in highway safety investigations. There are, however, many potential sources of error in WIM measurements which make it difficult for data collectors to evaluate data accuracy and consistency.


For over a decade, the Federal Highway Administration (FHWA) Long-Term Pavement Performance (LTPP) program collected a massive amount of WIM data, along with information about the performance of WIM equipment. This includes the WIM validation and calibration data from 24 LTPP Specific Pavement Studies (SPS) test sites across North America. This and other data sets provide an opportunity to develop more advanced WIM tools to help state highway practitioners perform WIM site selection, sensor selection, maintenance, development of calibration procedures including frequency, and data quality acceptance. These tools could help improve WIM data accuracy and consistency by considering factors such as temperature and seasonal effects, vehicle speed, pavement condition, changes in truck population and configurations, data sampling frequencies, system age, and other factors.  




The objective of this research is to develop the next generation of tools and procedures to improve accuracy and increase reliability of WIM data through (1) more appropriate site selections; (2) WIM system selection, installation, calibration, and maintenance; (3) data analysis methods; and (4) quality control/quality assurance (QC/QA) procedures.




The NCHRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers' current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objective.


The research plan should: (1) include a kick-off teleconference with the research team and the NCHRP project panel within 1 month of the contract’s execution; (2) address the manner in which the proposer intends to satisfy the project objective; (3) be divided logically into phases and detailed tasks that are necessary to fulfill the research objective and include appropriate milestones and interim deliverables; (4) include one face-to-face meeting to review Interim Report 1 at the conclusion of the first phase; (5) include teleconference meetings (NCHRP will provide teleconference services) as needed;  (6) incorporate opportunities for the NCHRP project panel to review, comment and approve milestone deliverables; and (7) include a detailed implementation plan.


At a minimum, the research plan should include the following tasks:




Task 1. Conduct a literature review related to the management of variability and bias in WIM data.


Task 2. Conduct a comprehensive review of LTPP data sets and other appropriate high quality data sources to select data for use in the research.


Note: Additional LTPP WIM information (e.g., field calibration reports) may be accessed through LTPP InfoPaveTM.


Task 3. Quantify the influence of factors related to pavement, vehicle, environmental, sensor type, WIM data acquisition system, and traffic on the performance of the WIM sites by assessing the accuracy of WIM data from LTPP and other comparable high quality data sets. Use this information to establish a baseline for assessing the impact of these factors.


Task 4. Prepare an interim report that documents the work completed in Tasks 1 through 3. Include a detailed work plan for the work anticipated in Phase II.


Note: NCHRP approval of the proposed Phase II work plan is required prior to initiation. This shall occur at a face-to-face meeting with the NCHRP project panel to be convened in Washington, D.C. at TRB offices. TRB will cover the costs associated with meetings at TRB facilities, teleconference services, and panel member travel.




Phase II will require at a minimum, the following tasks:


Task 5. Use the developed baseline to compare and analyze other WIM data to diagnose and quantify the sources of error and their sensitivities related to each of the aforementioned factors.  


Task 6. Develop and test practical tools for a variety of existing WIM data sets from various geographical areas, and with different influencing factors (e.g., pavement condition, sensor type, etc.) to determine which provide greater accuracy, consistency, and cost effectiveness.


Note: Should software be proposed, data and tools must be portable into LTPP InfoPaveTM for maintenance by FHWA.


Task 7. Based on the results of the data analysis, develop a stand-alone document that provides guidance for practical implementation of the research results by state transportation agencies, that at least includes improved procedures for: appropriate site selections; WIM system selection, installation, calibration and maintenance; data analysis methods; and QC/QA.


Task 8. Prepare final deliverables that fulfill the research objective and documents the conduct of research. The final deliverables also will include an executive summary, stand-alone guidance, recommendations for prioritized research needs, and outreach and presentation materials.

Final Deliverables should include:


1. A final report documenting the entire research effort including prioritized recommendations for future research;


2. An executive summary of the project;

3. Stand-alone guidelines and associated tools for practitioners;


Note: If applicable, include any source code, databases, programs, software, software documentation, and clean data sets developed under this project in USB or other pre-approved format. See Special Note H.


4. A PowerPoint presentation describing the background, objectives, research approach, findings, and conclusions;


5. A webinar conveying the research results and findings; and


6. A stand-alone technical memorandum titled “Implementation of Research Findings and Products” (see Special Note D for additional information).


Proposers may recommend additional deliverables to support the project objective.


Note: Following receipt of the draft final deliverables, the remaining 3 months shall be for NCHRP review and comment and for research agency preparation of the final deliverables.




A.  Item 4 of the proposal, the Research Plan, shall not exceed 25 pages, in 12-point font or larger. This does not include the detailed scheduled or the detailed budget. Item 5 of the proposal shall be limited to 1 page of biographical information for each person.


B. Proposals should include a task-by-task breakdown of labor hours for each staff member as shown in Figure 4 in the brochure, "Information and Instructions for Preparing Proposals" (http://onlinepubs.trb.org/onlinepubs/crp/docs/ProposalPrep.pdf). Proposals also should include a breakdown of all costs (e.g., wages, indirect costs, travel, materials, and total) for each task using Figures 5 and 6 in the brochure. Please note that TRB Cooperative Research Program sub awards (selected proposers are considered sub awards to the National Academy of Sciences, the parent organization of TRB) must comply with 2 CFR 200 – Uniform Administrative Requirements, Cost Principles, and Audit Requirements for Federal Awards. These requirements include a provision that proposers without a "federally" Negotiated Indirect Costs Rate Agreement (NICRA) shall be subject to a maximum allowable indirect rate of 10% of Modified Total Direct Costs. Modified Total Direct Costs include all salaries and wages, applicable fringe benefits, materials and supplies, services, travel, and up to the first $25,000 of each lower-tier sub award and subcontract. Modified Total Direct Costs exclude equipment, capital expenditures, charges for patient care, rental costs, tuition remission, scholarships and fellowships, participant support costs and the portion of each lower-tier sub award and subcontract in excess of $25,000.


C. NCHRP wishes to award the contract for NCHRP Project 20-50(20) for a fixed price of $350,000. This amount will not be subject to any adjustment by reason of the contractor’s cost experience in the performance of the contract.  In addition to providing a detailed budget, the proposer should provide a proposed schedule of project milestones, deliverables, and progress payments tied to the detailed budget and schedule which will be inclusive of specific dates. For budgeting purposes, proposers should assume that (1) NCHRP will provide access to web-enabled teleconference services and (2) 1 in-person meeting with the NCHRP project panel will be held in Washington, DC. NCHRP will pay panel members’ travel costs for the meeting.


D. The NCHRP is a practical, applied research program that produces implementable products addressing problems faced by transportation practitioners and managers. The benefits of NCHRP research are realized only when the results are implemented in state DOTs and other agencies. Implementation of the research product must be considered throughout the process, from problem statement development to research contract and beyond completion of the research. Item 4(c), "Anticipated Research Results," must include the following: (a) the "product" expected from the research, (b) the audience or "market" for this product, (c) a realistic assessment of impediments to successful implementation, and (d) the institutions and individuals who might take leadership in deploying the research product. The project panel will develop and maintain an implementation plan throughout the life of the project. The research team will be expected to provide input to an implementation team consisting of panel members, AASHTO committee members, the NCHRP Implementation Coordinator, and others in order to meet the goals of NCHRP Active Implementation: Moving Research into Practice, available at http://onlinepubs.trb.org/onlinepubs/nchrp/docs/NCHRP_ActiveImplementation.pdf.


E. Item 5 in the proposal, "Qualifications of the Research Team," must include a section labeled "Disclosure." Information relevant to the NCHRP's need to ensure objectivity and to be aware of possible sources of significant financial or organizational conflict of interest in conducting the research must be presented in this section of the proposal. For example, under certain conditions, ownership of the proposing agency, other organizational relationships, or proprietary rights and interests could be perceived as jeopardizing an objective approach to the research effort, and proposers are asked to disclose any such circumstances and to explain how they will be accounted for in this study. If there are no issues related to objectivity, this should be stated.


F. Proposals are evaluated by the NCHRP staff and project panels consisting of individuals collectively very knowledgeable in the problem area. Selection of an agency is made by the project panel considering the following factors: (1) the proposer's demonstrated understanding of the problem; (2) the merit of the proposed research approach and experiment design; (3) the experience, qualifications, and objectivity of the research team in the same or closely related problem area; (4) the plan for ensuring application of results; (5) the proposer's plan for participation by Disadvantaged Business Enterprises--small firms owned and controlled by minorities or women; and (6) the adequacy of the facilities.


Note: The proposer's plan for participation by Disadvantaged Business Enterprises should be incorporated in Item 12 of the proposal.


G. Copyrights - All data, written materials, computer software, source code, graphic and photographic images, and other information prepared under the contract and the copyrights therein shall be owned by the National Academies of Sciences, Engineering, and Medicine. The contractor and subcontractors will be able to publish this material for non-commercial purposes, for internal use, or to further academic research or studies with permission from TRB Cooperative Research Programs. The contractor and subcontractors will not be allowed to sell the project material without prior approval by the National Academies of Sciences, Engineering, and Medicine. By signing a contract with the National Academy of Sciences, contractors accept legal responsibility for any copyright infringement that may exist in work done for TRB. Contractors are therefore responsible for obtaining all necessary permissions for use of copyrighted material in TRB's Cooperative Research Programs publications. For guidance on TRB's policies on using copyrighted material please consult Section 5.4, "Use of Copyrighted Material," in the Procedural Manual for Contractors.


H. The selected contractor shall provide protocols for testing, maintenance and troubleshooting and deliver the following derived products if applicable: (1) developed computer databases, (2) programs, (3) software (including source code, transportability options, object code listings, design details, algorithms, processes, flow charts, formulae, and related material that would enable the software to be reproduced), and (4) software documentation developed during this research study. These deliverables shall become the exclusive property of the National Academies of Sciences, Engineering, and Medicine.


I. Proposers are encouraged to be familiar with the following documents and to take them into account when developing the proposed research plan.


1. FHWA IF 10-018, WIM Data Analyst’s Manual: https://www.fhwa.dot.gov/pavement/wim/pubs/if10018/if10018.pdf


2. LTPP Field Operations Guide for SPS WIM Sites Version 1.0, July 6, 2012


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