This article was last updated on July 8, 2025. It originally published on June 19, 2025.

Big changes are coming to Tremaine Road, and they’re designed to make your drive safer, smoother, and more efficient for years to come!

We’re entering the final phase of a major infrastructure upgrade that includes:

• a brand-new, four-lane bridge
• a realigned roadway for better north-south connectivity
• a future interchange that will provide direct access to Highway 401

Let’s walk you through what’s changing, how it may affect your commute, and how this project supports long-term regional growth.

What’s changing and when

We're excited to announce the new bridge is officially open! This new route will improve traffic flow and safety between Steeles Avenue and Campbellville Road. The new bridge will open with two lanes and will eventually be four lanes upon project completion.

Now that the new road is open, we’ll begin demolishing the old two-lane bridge over Highway 401. This will require some permanent and temporary closures and detours. Please read on for details.

Key dates and detours

Permanent closure of the existing Tremaine Road bridge

• When: Starting Monday, July 7, 2025 (weather permitting).
• What to Expect: The old bridge will be permanently closed. Motorists will be redirected to the new bridge via clearly marked detours.

Detour routes:

• Southbound: Use Detour 4 via Campbellville Road to access the new bridge.
• Northbound: Use Detour 3 via Existing Tremaine Road to access the new bridge.

Temporary overnight closure of Highway 401

• When: 9 p.m. Saturday, July 12 to 9 a.m. Sunday, July 13, 2025
• Why: To safely demolish the old bridge
• What to do: Highway 401 will be temporarily closed between Regional Road 25 and Guelph Line. Eastbound and westbound traffic will detour to Campbellville Road. Traffic control (including police and flag persons) will be in place, and detour signage will be clearly marked.

Coming soon: A new interchange for faster highway access

One of the most exciting features of this project is the new interchange connection to Highway 401, currently expected to open in December 2026.

This interchange will:

• provide direct access to and from Highway 401
• reduce travel times for commuters and commercial vehicles
• improve emergency response access
• support future growth and development in the region

This is a game-changer for local and regional mobility, especially as Halton continues to grow.

Why this project matters

This road and bridge upgrade is part of Halton’s broader commitment to building infrastructure that supports long-term growth. With a AAA/Aaa credit rating and a $9 billion 10-year capital plan, Halton is making strategic investments in roads, bridges, water and wastewater systems, and more. These improvements are designed to:

• support population and employment growth
• improve transportation networks
• enable future housing and economic development

By investing in key infrastructure today, we’re building a stronger, more connected Halton for tomorrow.

Stay informed

We’re working closely with our partners at the Ministry of Transportation (MTO) and our local municipalities to keep you informed and moving safely. We will also continue to provide important updates through this blog and on our corporate social media channels:

Follow us for updates:

• Facebook (external link)
• Instagram (external link)
• X (formerly Twitter) (external link)

For Highway 401 updates: Visit the MTO website or follow them on X.

Questions? Call 311 or email accesshalton@halton.ca

Thank you for your patience

We know construction can be disruptive, and we appreciate your patience as we complete this essential infrastructure work. Every improvement brings us one step closer to a safer, more efficient transportation network for everyone. We will continue to make every effort to complete the construction work as quickly as possible to minimize the impact of the closure. Thank you for your support.