Is a Protocol for Measuring Aged Retroreflective Sheeting Warranted? Retroreflectivity Measurements of 191 Trailers from 36 States

Since December 1, 1993, all trailers are required to be equipped with retroreflective sheeting. After the initial installation the sheeting will begin to age and the performance of the sheeting will decrease. No requirements exist for testing or refreshing the sheeting, leading to the two goals of this study. In Part 1, a handheld retroreflectometer was used to obtain readings from 10 in-use trailers. Measurements were made at 5 cm (2 inches) increments. When the sheeting on these trailers was cleaned, the measured values increased by more than 1.3 times. Based on the results, a measurement protocol was developed for testing at road side locations. Employing this sampling protocol, in Part 2 of this study, measurements were made of the retroreflectivity of 191 randomly selected trailers at DOT inspection locations and rest areas in 5 States. This testing required less than 15 minutes when conducted by a single person. Significant decreases in retroreflectivity were found to be associated with trailer age (median age 9 years) and level of dirtiness. Dirtiness was found to decrease retroreflectivity readings by approximately 25%. Of the measurements on each trailer, 34% were less than the minimum standard for white sheeting and 26% were less than standard for red sheeting. The increasing age of trailers correlated with the probability of readings that were below standard. Together, the findings suggest the need for more frequent testing of in-use retroreflective sheeting. The proposed test method is both accurate and simplistic to be used by police and safety officials.

  • Supplemental Notes:
    • This paper was sponsored by TRB committee ANB70 Standing Committee on Truck and Bus Safety.
  • Corporate Authors:

    Transportation Research Board

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Authors:
    • Muttart, Jeffrey W
    • Dinakar, Swaroop
    • Suway, Jeffrey
    • Kuzel, Michael
    • Lohf, David W
    • Maloney, Timothy
    • Wheat, Arnold G
  • Conference:
  • Date: 2017


  • English

Media Info

  • Media Type: Digital/other
  • Features: Photos; References; Tables;
  • Pagination: 12p
  • Monograph Title: TRB 96th Annual Meeting Compendium of Papers

Subject/Index Terms

Filing Info

  • Accession Number: 01628217
  • Record Type: Publication
  • Report/Paper Numbers: 17-06767
  • Files: TRIS, TRB, ATRI
  • Created Date: Dec 8 2016 12:47PM