Retroreflectivity Maintenance
Control Sign Method
In this method, a control sample of signs is used to represent the total population of an agency’s signs. The retroreflectivity of the control signs is monitored at appropriate intervals and sign replacement is based on the performance of the control signs. The following factors provide additional information about using this method:
- An agency develops a sampling plan to determine the appropriate number of control signs needed to represent the agency’s sign population.
- Control signs may be actual signs in the field or signs installed in a maintenance yard to serve specifically as control signs.
- The retroreflectivity of the control signs should be monitored following the procedures outlined for one of the assessment methods.
- All field signs represented by the control sample need to be replaced before the retroreflectivity levels of the control sample reach the minimum levels.