Construction of the SR 125 toll road started in September 2003; it was projected to open in 2006. Over the next few years, 1.5 million cubic meters of rock were blasted through in 160 separate explosions to allow for the interchange with SR 54 to be built. In 2005, the road was given the South Bay Expressway name. The South Bay Expressway extended SR 125 southward from SR 54 to Otay Mesa. This toll road was one of four privately financed toll highway projects, including the 91 Express Toll Lanes, that were approved in 1990; it was also one of two toll roads financed and controlled by both public and private sources, although the 91 Express Lanes, the other road, soon became entirely publicly owned. A partnership known as the South Bay Expressway operated the road, while an Australian company, Maquarie Group Ltd., handled financial and construction matters.