b1b4170c_cal_Agencies___FHWA_HRT_07_042__Reported_Impacts
[Agency/Location] Texas DOT (8) [Comments] The AASHTO Task Force participated in these exercises and similarly found the need to replace about three times more signs than would needed to satisfy the minimum levels. Usefulness of the visual inspections method led to the proposal that agencies be allowed to use it instead of measurement methods. TF agreed that it may be appropriate to alter the contrast criteria. [Implications] The results suggest that the minimum values will not affect agencies as much as might be expected. The field exercises demonstrated the value of night inspections to find a multitude of possible problems that adversely affect night visibility. [Reported Impacts] 
Texas DOT sign crews reviewing 50 signs in training program suggested replacement of more signs than might be necessary under the proposed FHWA minimum requirements. Findings raised questions about the appropriateness of the contrast ratio aspect of the requirements.
Maintaining Traffic Sign Retroreflectivity: Impacts on State and Local Agencies - FHWA-HRT-07-042