In a rural area, how much lower may a secondary sign be mounted compared to a primary sign?

In a rural area, secondary signs are often mounted 1 foot lower than primary signs to maintain effective visibility and communication with drivers. This practice is based on guidelines that ensure secondary signs are still discernible to approaching traffic while allowing the primary sign to take precedence in visibility and importance.

By keeping secondary signs slightly lower, it creates a clear visual hierarchy that helps drivers quickly identify key information. This difference in height can be particularly important in rural areas, where road conditions and sight distances can vary, ensuring that all signs are effectively positioned for the safety and awareness of drivers.