Where can the suggested advance warning sign spacing for different types of roadways be found?

The suggested advance warning sign spacing for different types of roadways can be found in the Manual on Uniform Traffic Control Devices (MUTCD). This comprehensive document provides federal standards for all traffic control devices, including guidelines on the proper placement and spacing of warning signs. The MUTCD is critical for ensuring uniformity in traffic control across the United States, enhancing safety and reducing confusion for drivers navigating through various roadways, including work zones.

In contrast, while State Traffic Manuals may provide specific regulations that reflect local needs, they are based on or influenced by the guidelines established in the MUTCD. National Highway Standards and Statistical Traffic Reports do not generally include detailed signage guidelines; rather, they focus on broader standards and the collection of traffic data, respectively. Thus, the MUTCD is the authoritative source for determining advance warning sign spacing.