The excavator, Arthur Evans, believed that these openings allowed the free passage of water flowing down the neighbouring hillside into the stream, and supported the road across the stream. According to the reconstruction drawing by T. Fyfe, they were originally arched. The viaduct is preserved to a length of 20.5m., a height of approximately 2.60m. and a width of 4.5m. However, Evans thought that it would originally have been 10 m. high and the road across it over 5m. wide.
The viaduct is dated to the Neopalatial period but there was probably an older bridge on the same site, its remains identifiable in the lowest courses of the surviving structure. The viaduct fell out of use in the LM III period.