6. Highway 403 & 6 Mainline

Highway 403 & Highway 6 Mainline – Evaluation of Alternatives

Alternative 2 (the Preferred Alternative)

  • Slightly higher construction costs
  • Similar fill requirements and construction staging to Alternative 3
  • The addition of lanes along both Highway 403 and Highway 6 will increase capacity and traffic flow through both highway corridors, but also increase traffic noise and reduce local air quality more than adding lanes to only Highway 403.
  • Similar impacts to the natural environment as Alternative 3

This alternative includes adding one lane in each direction on Highway 403 and one Highway 6 southbound lane.

Alternative 3 (not preferred)

  • Slightly lower construction costs,
  • Similar fill requirements, construction staging and impacts to the natural environment as Alternative 2
  • Less impact on the socio-economic environment due to lanes only being added to Highway 403.
  • Will only increase traffic capacity of Highway 403 and impact local noise and air quality

This alternative includes adding one lane in each direction on Highway 403​.

5. Evaluation of Alternatives

Evaluation of Alternatives

  • The criteria outlined in the following table have been used to evaluate alternatives
  • A Reasoned Argument (trade-off) method of evaluation was used to identify the advantages and disadvantages in order to select the preferred alternatives
  • Alternatives were evaluated based on their ability to address future capacity and operational issues; improve safety conditions; address future rehabilitation needs, and minimize impacts to the natural, social, economic, and cultural environment
  • Highway 6/York Rd Interchange Evaluation Criteria included the feasibility of accommodating a Carpool Lot

Evaluation of Alternatives - Criteria

Evaluation Component ​


Natural Environment​

  • Fish and Fish Habitat​

  • Terrestrial Ecosystems (vegetation, wildlife, wetlands, etc.)​

  • Designated Natural Area (ANSI/PSW etc.)​

  • Groundwater

  • Species at Risk​

  • Surface Water

Socio-Economic Environment​

  • Aesthetics​

  • Noise​

  • Air Quality​

  • Community Effects (residential, commercial, institutional, Property Impacts etc.)​

  • Agricultural Operations​

  • Commercial/ Industrial Operations ​

  • Approved Plans & Policies 

  • Contaminated Properties & Waste Management

Cultural Environment​

  • Archeological Resources​

  •  Built Heritage and Cultural Landscapes​

  • Indigenous Lands

Transportation, Engineering and Cost​

  • Traffic Operations & Safety​

  • Construction Staging ​

  • Utilities ​

  • Excess Materials (more, less equivalent) ​

  • Cost (construction cost)



Evaluation of Alternatives

  • At the onset of this study, a numbering system was produced for the initial long list of alternatives generated.
  • For consistency, the numbering system is maintained for the shortlisted alternatives (as presented at PIC #1) considered throughout the study.
  • The following displays provide a summary of the evaluation of alternatives and the selected preferred alternatives



4. Study Schedule

Notice of Study Commencement

January 2020

Site Visits / Field Investigations

December 2019 - November 2020

Generate Improvement Alternatives

February 2020 - June 2020

Public Information Centre #1

June 25, 2020

Assess and Evaluate Improvement Alternatives

April 2020 - October 2020 

Identify and Develop Preferred Improvement Alternative

October 2020 - January 2022

Public Information Centre #2 (WE ARE HERE)

March 10, 2022

Future Develop Mitigation Strategies

November 2021 - July 2022

Prepare TESR

June 2022 - September 2022

30-Day Public Review

September 2022

*Note: Schedule is subject to change

3. Consultation

Summary of PIC#1

  • The Ministry of Transportation held the first Online PIC on June 25, 2020 and received questions and comments via the study website.
  • A total of 103 individuals visited the Study Website during the Virtual PIC and 71 individuals viewed the PIC #1 Presentation Video.
  • Over the 45-day comment period, a total of 27 comments were received.
  • Various alternatives were identified and presented at PIC #1.

Key Comments Received from PIC#1

  • How the MTO Highway 5/Highway 6 Interchange Study relates to this study.
  • Questions regarding noise and air quality impacts from the higher traffic volumes.
  • Question regarding noise mitigation measures and impacts to the existing noise barriers.
  • Concerns regarding the Highway 6/York Road interchange and existing sightline issues.
  • Concerns regarding impacts to the natural environment and Royal Botanical Gardens.
  • Support for elimination of the left-hand on-ramp to Highway 403 eastbound.

We’ve listened to the comments raised and are addressing these issues in the development of the Recommended Plan.

Purpose of Public Information Centre (PIC #2).

The purpose of this Public Information Centre (PIC) is to present and receive feedback on the following aspects of the project:

  • The Evaluation of Alternatives
  • Details of the Recommended Plan
  • Mitigation and Environmental Protection Strategies
  • Next steps & how to stay informed

We Want Your Feedback!

2. Study Process

This study is following the requirements for a Group ‘B’ project under the MTO Class Environmental Assessment for Provincial Transportation Facilities (2000).

A Transportation Environmental Study Report (TESR) will be prepared and made available for public and agency review for a period of 30‐days at the completion of the study which will document the following:

  • A description of the evaluation of alternatives and selection of the preferred alternative
  • A summary of potential environmental effects and mitigation measures
  • A summary of consultation undertake throughout the project


Notification, advising of the times and locations of the availability of the TESR for review will be published in local newspapers and mailed to those on the Project Contact List.

To be added to the Project Contact List, please complete a comment sheet or email the Project Team at:


Notice of Study Commencement

January 2020

Generate and Assess Preliminary Design Alternatives

Public Information Centre #1

June 2020

Evaluate and Select the Preliminary Preferred Design Alternative

Public Information Centre #2 (WE ARE HERE)

March 2022

Develop Preferred Preliminary Design Alternative

Notice of Study Completion and Transportation Environment Study Report (TESR) Submission

TESR 30-Day Public Review

Environmental Clearance

1. Project Overview

The Ontario Ministry of Transportation (MTO) has retained AECOM Canada Ltd. (AECOM) to undertake a Class Environmental Assessment (EA) and Preliminary Design Study for the improvements to Hwy 403 from Grindstone Creek westerly to Old Guelph Road on Highway 403, and Highway 6 from Highway 403 to Bruce Trail.

Study Scope

Identify short-term and long-term improvements of Highway 403 and Highway 6 Interchange that will allow the next round of infrastructure rehabilitation / renewal to accommodate future traffic needs of Highway 403 within the study limits.

Project includes the following structures:

  • 14 Bridges
  • 3 Structural Culverts
  • 15 Retaining Walls

Study Area Map

Key Objectives of the Study

Key objectives of the study include:

Short-term Plans:

  • Identifying the rehabilitation needs of all structures within the study area.
  • Developing a preferred staging and contract sequencing strategy for all structures.

Long-term Plans:

  • Exploring long-term improvements along the Highway 403 and Highway 6 corridors.
  • Developing long-term improvements for Highway 403 and Highway 6 Interchange so that an ultimate interchange design can be established, and land protected.
  • Identifying the widening and/or replacement needs of all structures within the study area.
  • Identifying areas of future roadway widening to allow for increased capacity.

Existing Left-hand Exit From Highway 403 Eastbound to Highway 6 Northbound

Existing Ramp from Highway 6 Southbound to Highway 403 Eastbound