What is the recommended advanced warning sign spacing in urban areas with low speeds?

In urban areas where vehicle speeds are low, the recommended advanced warning sign spacing is typically set at 100 feet. This closer spacing is crucial for ensuring that drivers are adequately prepared for upcoming conditions, hazards, or changes in roadway features, especially in areas where stopping distances are shorter due to slower speeds.

In these environments, drivers often have less time to react to signs, making it essential for warnings to be more frequent and easier to notice as they approach. This spacing takes into account both the reaction times of drivers and the way urban areas are typically designed, with more visual stimuli and potential distractions compared to rural settings.

Longer spacings, such as 200 feet, 300 feet, or 400 feet, do not provide adequate advance notice for situations commonly faced in urban settings, which can lead to abrupt stops or unsafe maneuvers as drivers react to signs too late. Therefore, 100 feet is recommended to enhance safety and ensure appropriate driver awareness.