What is the suggested advanced warning sign spacing for freeways and expressways?

The suggested advanced warning sign spacing for freeways and expressways is typically 1000 feet. This distance allows drivers sufficient time to perceive and react to upcoming conditions or changes in traffic patterns, especially at high speeds characteristic of these roadways.

In the context of traffic management, advanced warning signs are crucial for alerting drivers about upcoming work zones, lane closures, or other hazards. The distance of 1000 feet strikes a balance between providing enough notice for drivers to prepare for a change while not overwhelming them with signs placed too far in advance. This spacing is supported by guidelines that take into account the speed limits found on freeways and expressways, where vehicles travel at higher speeds compared to other types of roads.

Other distances, such as those provided in the incorrect options, may either be too far to be effective or are not recommended for typical traffic situations on such roadways, leading to potential confusion or obstacles in driver response times. Thus, the choice of 1000 feet aligns with established standards for enhancing road safety.