Building an interchange at 6th Line and Highway 400 in Innisfil isn't going as slow as a Friday afternoon cottage crawl, but at times it feels like it.
Innisfil council recently received an update from staff on the project, which has been gestating since the town’s 2013 transportation master plan. A preliminary design plan and addendum to the previously completed environmental study report are expected this fall, staff indicated.
The town got the ball rolling by completing a municipal class environmental assessment in 2017 for the future interchange and the environmental study report generated was approved.
Last year, the Ontario Ministry of Transportation (MTO) gave the project the green light and began to review the studies the town had already completed.
Further consultation throughout the past 12 months between the town, the MTO and project consultant Stantec identified several issues that need to be addressed in order for the project to go forward, including:
- Updating the interchange design to meet current standards and best practices
- Realigning the proposed interchange ramps
- Replacing the proposed roundabouts at the ramp terminals with traffic signals
- Replacing the existing Innisfil Creek culvert crossing under the 400 with new bridges
- Installing new bridges for the crossings of Innisfil Creek for the future west-to-south and south-to-east/west ramps
The need for these changes is largely driven by three factors.
The previous environmental assessment had assumed a design speed of 120 kilometres per hour on Highway 400. That has since been updated to 130 km/h, which requires the geometry of the future interchange to be re-evaluated, particularly with the ramps.
Changes to the ramps would require additional land to be purchased to complete the project.
The 2017 report looked at traffic patterns out to 2041 and determined roundabouts would be sufficient at the ramp terminals. Subsequent studies in the seven years since the environmental assessment indicate traffic past 2041 will likely exceed the recommended volume for roundabouts and signalized intersections are the best way to proceed.
The new interchange would also require adjustments to Highway 400 as well, which could cause headaches for motorists during construction. Currently, the 400 crosses Innisfil Creek via a structural culvert, which would have to be extended to accommodate the interchange.
However, as the culvert is reaching the end of its service life, constructing a new bridge at this location is comparable in cost and will be recommended. Similarly, bridges will be utilized for the future ramp crossings of Innisfil Creek.
The full study update is available by clicking here.
Staff reiterated the town’s support for the project in the report prepared for council.
“The future interchange is expected to have a profound, positive impact on travel throughout the town of Innisfil,” the report stated. “Currently, there are no interchanges on Highway 400 between Highway 89 and Innisfil Beach Road, a distance of nearly 10 kilometres.
"An interchange at the 6th Line would improve Highway 400 access for the Innisfil Heights Employment Area, the future Orbit development, the future Innisfil GO station, and the settlements of Alcona, Lefroy, Belle Ewart, and Churchill. Having another interchange within the town is also expected to improve emergency services response times," the report added.
The town is a co-proponent, but the construction is ultimately an MTO project, council was told at its June 26 meeting.
