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Sign Life Expectancy on Low Volume Roads in Iowa

Date and Time: Monday, July 24: 3:30 PM - 5:00 PM
Location: Grand Ballroom C

 

Lead Presenter: David Veneziano

Safety Circuit Rider, Iowa Local Technical Assistance Program, Institute for Transportation, Iowa State University

Speaker Biography

David Veneziano is Safety Circuit Rider with the Iowa Local Technical Assistance Program (LTAP) at the Institute for Transportation at Iowa State University. Dr. Veneziano earned his Ph.D. in transportation engineering from Iowa State University in 2006. He has over 16 years of experience in various aspects of transportation research, including safety and operational analysis, winter maintenance applications, Intelligent Transportation Systems and remote sensing. In addition, his experience includes outreach and training activities on safety and maintenance topics for multidisciplinary local and state transportation agency staff. David provides on-call technical assistance to provide local agencies with information and guidance on various technical matters related to safety, operations and signing.

Co-Authors 

Presentation Description/Paper Summary

Traffic signs provide warning and guidance information to drivers 24 hours a day. They also represent a significant maintenance and replacement concern and cost for agencies with the advent of retroreflectivity requirements. In some cases, agencies choose to replace their signs in conjunction with the end of the manufacturer warranty period or other time intervals to maintain sign retroreflectivity. However, this could result in signs being replaced while they still exceed their minimum retroreflectivity requirements, with labor and material costs being incurred years before necessary. This research evaluated retroreflectivity data from in-service signs in Iowa to determine expected sign life values. It evaluated 10,799 retroreflectivity data points across three different sheeting materials for a variety of sign types. A total of 65 linear regression models were developed to evaluate signs by sheeting type, age and sign category (regulatory, warning and guide), as well as directional orientation. The results indicated that all sheeting materials, sign types, and sign directions were predicted to have lives of at least 10 years before falling below MUTCD minimums. Plots of retroreflectivity versus age indicated that many signs remained well above the MUTCD minimums at the predicted age where failure was expected. In general, the predicted lives for a material/sign type/direction combination were greater than five years longer than manufacturer warranty periods. For conservative purposes, agencies could consider a sign to be approaching minimum retroreflectivity levels at approximately five years past the manufacturer warranty based on the research results.

Presentation File

Poster