Simulation-Based Evaluation of Traffic Sign Retroreflectivity Maintenance Practices

Abstract

A new highway sign minimum retroreflectivity standard issued by the Federal Highway Administration (FHWA) is compelling agencies to evaluate how to comply while remaining within their budgets. This paper presents the results from a unique microscopic sign system simulation developed to quantitatively evaluate the effectiveness of various sign management practices. The analysis focused on three management methods—nighttime visual inspection, blanket replacement, and expected sign life—and two key sign maintenance functions, sign damage and replacement. The analysis found that sign managers should make prompt replacement of damaged signs a priority. The blanket replacement method was less cost-effective than the nighttime visual inspection method. The expected sign life method was competitive on costs with the visual inspection method while maintaining similar sign conditions. Training inspectors to be more accurate can realize further savings. Skipping inspection or replacement one year, or having an insufficient sign budget, can lead to degraded sign condition levels. The authors offer five best practices that agencies can consider when making sign management decisions.