John Marshall writes of what he called First Street, "The northern part of this street, 145 feet in length, had been dug by Mr. Hargreaves in 1925-6, the rest of the street, some 300 feet in length, was completely exposed by me down to the Intermediate level, the work involving the removal from the street itself of a 10 ft. thick layer of closely packed debris ... The width of the street averages 30 feet and it is the only street so far excavated at Mohenjo-daro that could have been used for wheeled traffic, if wheeled traffic was permitted inside the town. No actual traces of wheeled vehicles have so far been found at Mohenjo-daro, but that they were used in this period is patent from several terra cotta wheels of toy carts brought to light at this site as well as from a tiny model bronze cart found at Harappa. The street is not paved with bricks or concrete anywhere ... The exact purpose of a small brick circle in the middle of the street ... is not apparent" (Marshall, Mohenjo-daro, pp. 187-8).
See also First Street, Mohenjo-daro.