Signs are very important to motorist, bicyclist and pedestrian safety, particularly regulatory and warning signs. These signs can fade, be painted over, get knocked down, be stolen, be blocked from view because of vegetation or man-made features, cease to apply to the current situation, or be dirty. Occasionally, someone may even add signs that are not appropriate or consistent with the control of traffic or driver's needs. Checking the existing signs against sign inventory can identify any discrepancies and resolve those discrepancies before they contribute to an accident.

Signs should be checked at least twice a year as conditions dictate. Desirable times are after winter and before the start of the school year. (This cycle provides for identifying winter damage and blocked visibility as a result of new vegetation growth.) As previously mentioned, special reviews should be conducted after bad storms when drifting snow blocks visibility or trees are blown down.

During sign checks it is also desirable to clean dirty signs and refurbish faded or damaged signs. The inspectors should keep a record of all actions taken and recommended. These records should be added to the sign inventory.