What is the minimum visibility distance for a portable change message sign (PCMS)?

• A. 1/4 mile
• B. 1/2 mile
• C. 1 mile
• D. 2 miles

Answer: (B)

The minimum visibility distance for a portable change message sign (PCMS) is established to ensure that drivers can read the messages displayed in sufficient time to respond appropriately. A visibility distance of 1/2 mile allows for adequate reaction time, especially in highway or high-speed environments where drivers approach the sign at higher velocities. This distance is crucial for safety, as it provides a buffer for comprehension and decision-making.

Establishing the visibility threshold at 1/2 mile takes into account factors such as sign legibility, the speed of approaching vehicles, and the need for timely information dissemination to avoid sudden stops or erratic driving behavior. The intention is to ensure that all drivers, regardless of their speed, can get clear information well in advance of any changes in traffic patterns or conditions that the PCMS is meant to convey.