For urban areas with high speed limits, what is the suggested advanced warning sign spacing?

In urban areas with high speed limits, the suggested advanced warning sign spacing is important for ensuring the safety of both drivers and flaggers. The correct spacing of 350 feet allows drivers adequate time to react to the upcoming conditions, such as construction zones or changes in road configurations. This distance is designed to provide enough advance notice while considering the higher speeds at which vehicles can travel in urban settings. Proper signage placement is vital to minimize confusion and to facilitate smooth traffic flow, which ultimately enhances safety for all road users.

The other distances suggested do not align with the recommended practices based on the guidelines for urban environments with high speed limits, as they may either be too short, not allowing sufficient reaction time, or too long, which could diminish the visibility and effectiveness of the warning signs.