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Retroreflectivity Maintenance
Note: the Interactive Walkthrough in the Steps to Implementation section uses a simplified subset of the following methods.
(the following is adapted from FHWA “Maintaining Traffic Sign Retroreflectivity”)
There are several methods that agencies can use to maintain sign retroreflectivity above the minimum maintained retroreflectivity levels. These minimum levels were developed to provide agencies with a general target for maintaining sign retroreflectivity. The existence of minimum retroreflectivity levels is not intended to imply that agencies need to measure the retroreflectivity of every sign in their jurisdictions. Instead, these methods provide agencies with options that best suit their operations and that will help improve nighttime sign visibility.
Sign maintenance methods can be divided into two groups:
Assessment Methods
Assessment methods involve the actual evaluation of individual signs. In this section:
- Visual Nighttime Inspection Method
- Calibration Signs Procedure (with checklist)
- Consistent Parameters Procedure (with checklist)
- Comparison Panels Procedure (with checklist)
- Measured Retroreflectivity Method
Management Methods
Management methods involve tracking and/or predicting the retroreflectivity of signs through an inventory process. In this section:
The FHWA has identified several assessment and management methods for maintaining sign retroreflectivity in a manner that is consistent with the minimum retroreflectivity levels. Agencies also have the flexibility to develop their own methods for maintaining sign retroreflectivity.