FINAL REPORT for RESEARCH PROJECT 2001-16 (FHWA/NC
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FINAL REPORT For RESEARCH PROJECT 2001-16 (FHWA/NC/2002-017) A Sign Inventory Study to Assess and Control Liability and Cost By Stephanie C. Vereen Graduate Research Assistant Joseph E. Hummer, Ph.D., P.E. Associate Professor William J. Rasdorf, Ph.D., P.E. Professor Department of Civil Engineering North Carolina State University Raleigh, NC August 2002 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA/NC/2002-017 4. Title and Subtitle 5. Report Date A Sign Inventory Study to Assess and Control Liability and Cost August 2002 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Stephanie Vereen, Dr. Joseph E. Hummer, and Dr. William Rasdorf 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Department of Civil Engineering North Carolina State University Campus Box 7908 Raleigh, NC 27695-7908 11. Contract or Grant No. 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered North Carolina Department of Transportation Final Report Research and Analysis Group January 1, 2001 - June 30, 2002 1 South Wilmington Street Raleigh, NC 27601 14. Sponsoring Agency Code 2001-16 15. Supplementary Notes 16. Abstract The goal of this work was to determine, quantify, and present to the North Carolina Department of Transportation (NCDOT) alternative approaches for meeting the Federal Highway Administration’s (FHWA) proposed minimum levels of retroreflectivity for signs. This study used knowledge of the current NCDOT sign maintenance practices to synthesize a list of components and alternatives to comply with the standard. The fundamental contribution of the work lies in creating alternative methods to evaluating sign retroreflectivity to ensure compliance with a standard while minimizing the cost and labor required to do so. The four alternatives formulated were: 1) Continue with current inspection method, 2) Make improvements to current inspection method, 3) Implement a Sign Inventory Management System in addition to the current inspection method, and 4) A combination of alternative 2 and alternative 3. It was the recommendation of this report that, although the most costly, alternative 4, the combination of alternative 2 and 3, be adopted by NCDOT. It was also recommended that an evaluation be made periodically to determine what benefits and improvement in sign condition, if any, have resulted from the alternative’s implementation. 17. Key Words 18. Distribution Statement signs, retroreflectivity, standards, inventory, inspection 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 218 Form DOT F 1700.7 (8-72) Reproduction of completed page authorized ii DISCLAIMER The contents of this report reflect the views of the authors and not necessarily the views of the University. The authors are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of either the North Carolina Department of Transportation or the Federal Highway Administration at the time of publication. This report does not constitute a standard, specification, or regulation. iii ACKNOWLEDGEMENTS Significant assistance was provided for this project by several organizational units of the NCDOT. Of particular note are Ray Goff from Division 6, Tom Thrower from Division 10, and J. Dean Ledbetter from Division 11, who were of great assistance. Ron King and Susan Kunz of the Signing Unit provided unlimited information. In addition, Brad Hibbs and Frank Julian of the Federal Highway Administration, Chuck Congelton and Danny Stanley of Correction Enterprise and the Bunn Sign Shop, and Tim Foster and Lorraine Jennings of Highway Division 11 provided assistance. The entire NCDOT Research Unit, the Project 2001-16 Committee, and the late Mohammed Mustafa provided help and valuable feedback. This assistance is gratefully acknowledged. iv EXECUTIVE SUMMARY The State of North Carolina currently maintains approximately 78,000 miles of road and approximately 1 million signs. In the near future, the Federal Highway Administration (FHWA) is expected to release minimum levels for sign retroreflectivity. The pending guidelines will present several new issues to state transportation agencies responsible for sign placement and maintenance, including liability, safety issues, organizational concerns, and resource concerns such as labor and cost. “The implementation of retroreflectivity standards would create a need for accurate, reliable, and cost-effective method to review traffic signs in the field 1”. To date, no one has developed a system or methodology to meet the standards on a scale as vast as that faced by NCDOT. The main objective of this project is to determine, quantify, and present to NCDOT alternative approaches for meeting the standard. This project will identify a number of approaches, work with the NCDOT to select a subset of the most promising approaches, gather data and information to quantify the alternatives against various criteria, and present them to NCDOT. The result will be to lay out and quantify choices that would enable NCDOT to minimize costs, reduce liability, improve safety, and comply with the proposed standards. A literature survey revealed two reports formulated by FHWA in 1998. The first report used input from several state and local agencies to “evaluate the applicability and practicality of: the minimum-maintained levels of sign retroreflectivity proposed by FHWA and the hand-held retroreflectometer that measures signs retroreflectivity2.” The second report presented explanations and procedures to assist agencies in developing their own sign management systems to meet the minimum retroreflectivity requirements3” which was used as a guide in the sign management system section of this project. Other literature addressed issues such as how many signs may not be in compliance when the proposed standards are implemented, the cost to replace these signs, feedback from agencies on the standards and hand-held retroreflectometer evaluations. The current sign maintenance and inspection methods of NCDOT were observed and evaluated. A life cycle of a sign in North Carolina was created based on visits to the sign manufacturing plant in Bunn, NC, discussion with State Signing Engineers, and visits to State highway Divisions to see storage methods and accompany an actual nighttime sign inspection. 1 Black, K.L., McGee, H.W., and Hussain, S.F., Implementation Strategies for Sign Retroreflectivity Standards. NCHRP Report 346, Transportation Research Board, Washington, D.C. (April 1992). 2 McGee, Hugh W., and Taori, Sunil, “Impacts on State and Local Agencies for Maintaining Traffic Signs Within Minimum Retroreflectivity Guidelines” BMI, Vienna, VA (1998) 3 McGee, Hugh W. and Paniati, Jeffrey A., An Implementation Guide for Minimum Retroreflectivity v Two studies were performed in conjunction with this report to estimate the number of signs on North Carolina roads because an accurate approximation was unknown. These reports resulted in an estimate of approximately 11,300 signs on Interstate roads, 369,700 signs on primary routes and 605,000 signs on secondary routes. A main impetus for this report and concern of NCDOT with the proposed standards is driver safety. Another concern is liability issues and the state’s exposure to increased liability. The maximum amount that can be awarded to a defendant in a tort claim against the State was raised from $150,000 to $500,000 on June 30, 2000. The threat of another increase to $1,000,000 and the forthcoming implementation of the proposed minimum values as a standard expose DOT to a high potential for liability claims as a result of non-compliant signs. Although, history reveals that few claims are actually awarded any money (of the claims filed during 2001 that cited some type of signing concern as the cause -not necessarily retroreflectivity- no awards were made or the cases were still pending), the opportunity for high cost claims to occur will be increased. Research included exploring retroreflectivity and it’s principles, sign types and their classifications, sign sheeting types, and software and technologies available for measurement. Using the existing literature and information collected from NCDOT meetings and observations, a preliminary list of about 30 alternatives was generated. These alternatives were presented to the NCDOT research team to retrieve comments and feedback as to which alternatives they would like to see evaluated. The meeting resulted in four alternatives, which are: 1) Maintain nighttime visual inspection method (current method), 2) Maintain nighttime inspection method with improvements, 3) Implement a sign inventory management system, and 4) Combination of Alternatives 2 and 3. The four alternatives were outlined and costs were generated for each one. A spreadsheet to determine the accuracy of nighttime sign inspection method was created. It was also used to calculate how many signs would potentially not be in compliance after visual inspection. It was determined that the visual inspection method produces a fairly low percentage of signs that are potentially not in compliance after the inspection. It is anticipated that the percentage of signs potentially not in compliance for NCDOT are lower because of sign personnel experience and that accuracy would increase if improvements were made to inspector training. Requirements