To avoid name duplication, the Toronto portion of the northern branch was renamed Twyn Rivers Drive.

However, the street originally continued straight east into the Rouge valley, but that section was renamed Twyn Rivers Drive after the connection to Port Union Rd.

was made in the early 1950s, though the renaming was not applied to the entirety of the bypassed section (thus officially giving the street its two branches) beyond Altona Road just east of the Toronto-Pickering limits in Durham Region.

Further west, the road allowance became blocked in 1939 by the appropriation of land for a De Havilland aircraft plant and, after World War II, Canadian Forces Base Downsview.

A crescent-shaped section of road was finally constructed along the northern edge of the now former base in the 1970s, connecting Sheppard at Wilson Heights to Keele Street.