High-speed, high-volume highways depend on fully effective overhead signs. Therefore, it is essential that overhead signs be properly maintained at all times.

Except for supports, overhead signs should require less maintenance than ground mounted signs. This is a result of their mounting height and the materials the overhead signs are made of. Damage by vandalism is also less. However, when damage does occur, immediate measures should be taken to repair the damage if sign effectiveness is impaired. Most damage to overhead signs is caused by thrown objects and firearms, usually resulting in minor damage.