MTO completed the Preliminary Design and Class EA Study for the 26 km section of Highway 404 from 407 ETR to Green Lane, in the Regional Municipality of York from 2014 to 2016.

The objectives of the previously completed Preliminary Design study were to assess and identify rehabilitation, safety and operational improvements throughout the study corridor and develop a plan that includes contract staging and sequencing for future construction projects.

A Transportation Environmental Study Report (TESR) was prepared to document the potential environmental effects associated with the Recommended Plan, proposed mitigation measures and commitments to future work. The TESR was released for a 30-day public review in June 2016, and received environmental approval in August 2016.

The EA Approved Plan that will be further refined during this Detail Design Study includes: