How high must the letters on a STOP/SLOW paddle be?

Answer: C — 6 inches

The requirement for the height of letters on a STOP/SLOW paddle is established to ensure that the message is easily readable from a distance, allowing drivers to react appropriately to traffic control instructions. The standard height of 6 inches for the letters provides good visibility under various conditions, maintaining clear communication in work zones. This specification helps improve safety by ensuring that the paddle can be recognized and understood by motorists with enough time to respond safely. The choice of 6 inches not only meets visibility needs but also aligns with industry standards designed for effectiveness in temporary traffic control setups.