http://agathe.gr/guide/panathenaic_way.html
Panathenaic Way Numerous roads led in and out of the Agora square. By far the most important, however, was the broad street known as the Dromos or Panathenaic Way, the principal thoroughfare of the city ... Basins in the line of the channel caught sediment and helped keep the channel clean; those off to the side presumably provided water for draft animals. ... Limestone channel with water basins along the Panathenaic Way. ... It seems also to have served as the running track for foot races before a proper stadium was built, and as the training ground for the young recruits of the Athenian cavalry.