How did the royal road of Persia work?

The Royal Road of Persia was an ancient highway that facilitated communication and trade across the vast Achaemenid Empire. Stretching approximately 2,700 kilometers from Sardis in Anatolia to Susa in Persia, it featured well-maintained paths, rest stations, and relay stations for couriers. This infrastructure enabled messengers to travel swiftly, allowing for efficient governance and military mobilization. The Royal Road exemplified the administrative prowess of the Persian Empire and played a crucial role in its economic and cultural exchanges.