[5][7] After paralleling along the south side of a Canadian National rail line, Highway 39 returned onto Tecumseh Road.

After passing over a Canadian Pacific rail line, it ended at an intersection with Highway 2, which continued east to Tilbury.

[16][17][18] The DHO finally agreed to take over the route, assuming control over 22.9 kilometres (14.2 mi) of roads through Maidstone, Rochester and Sandwich East townships on July 11, 1934.

[23] Traffic levels increased over the following decades, with two at-grade crossings of the Michigan Central Railroad becoming the site of frequent deadly accidents.

In August 1951, the towns of Tecumseh and Belle River petitioned the DHO to construct a bypass along the south side of the tracks, avoiding both crossings.

The towns made a second request in March 1955,[25] to which the DHO agreed to conduct a survey into the need for a bypass that summer.

[28] In April 1958, the DHO announced that it would proceed with constructing the bypass, as it was not possible to widen the existing highway through Tecumseh.

[33] The provincial portion of the former route through Tecumseh, east of Manning Road, became Highway 39B briefly before being decommissioned on August 10, 1962.