Precast concrete
By 1950, the highway had been sealed from Perth to Southern Cross, and from a few miles west of Coolgardie to Kalgoorlie. Traffic in the Goldfields was light, with an average daily traffic of 44 vehicles between Southern Cross and Coolgardie, and 33 from Coolgardie to Kalgoorlie. The road was completely sealed by 1953. Between 1954 and 1956, sections of the highway between Perth and Southern Cross were improved. The works included increasing the seal width along of the road, reconstructing of road, and resealing . Precast concrete structures were used to replace two old, narrow wooden bridges.