What is the recommended advanced warning sign spacing for urban areas with low speed limits?

In urban areas with low speed limits, the recommended spacing for advanced warning signs is typically 100 feet. This distance allows drivers sufficient time to recognize the warning sign and respond appropriately, considering the slower speed of vehicles in these areas. The shorter spacing in urban settings is effective because it aligns with the driver's need to react quickly to potential hazards or changes in traffic conditions, which can occur frequently in such environments.

In contrast, longer spacing would be more suitable for higher-speed areas, where drivers need more time to adjust to upcoming conditions. The guideline for 100 feet is rooted in the principle of providing clear and timely information to enhance safety for both drivers and pedestrians in densely populated areas.