AMAC uses state-of-the-art cameras, advanced illumination techniques and computer software to allow a new objective assessment method system to calculate, at highway speeds, how signs actually appear to drivers.

Methods for Maintaining Traffic Sign Retroreflectivity *

Visual nighttime inspection Using actual retroreflectivity values removes subjectivity from inspection evaluation, maintaining adequate levels of safety while eliminating unnecessary replacement of signs.
Measured retroreflectivity Measures a wide set of aspects, including all sign backgrounds and legends; optimizes inspection time; removes all subjectivity; and uses driver’s point of view.
Expected sign life Sign sheeting material has proven to outlast sheeting warranties. By knowing the actual performance of the sheeting material signs can be replaced when they are actually not meeting the minimum standards rather than making assumptions as to the performance.
Blanket replacement By having actual retroreflectivity values of signs, only those that fail to meet the minimum standards will be replaced. This approach yields significant reduction in sign panel replacement and cost savings.
Control sign Control sign monitoring makes assumptions that signs in the field degrade at corresponding rates as the control array. Field conditions vary widely from the control site resulting in premature replacement.

* According to FHWA

Research has shown that a sign management program that utilizes measured retroreflectivity realizes significant cost savings over the functional life of sign sheeting materials. Alternate sign management approaches to sign assessment lead to material waste and signs being replaced significantly prior to their functional degradation.

The referenced white paper by Dr. Paul Carlson of the Texas A&M Transportation Institute provides some insights and considerations for developing a sign management program.

Before selecting a method to maintain sign retroreflectivity, there are key considerations an agency should consider. First, will the chosen method provide adequate protection from potential tort claims regarding marginal or inadequate retroreflectivity? Second, what will be the long-term cost to sustain the chosen method? This paper was written to provide fresh insights into these questions to assist agencies that are considering how to best comply with the MUTCD minimum sign retroreflectivity requirements.

Dr. Paul J. Carlson
Texas A&M Transportation Institute