Toronto, Canada – Ontario Highway 401 Highway 401, also known as the Macdonald–Cartier Freeway, runs through Toronto and is widely recognized as one of the busiest highways in the world. Key Facts: • 📍 Located in: Ontario, Canada • 🛣️ Length: About 828 km (from Windsor to the Quebec border) • 🚗 Through Toronto: Some sections carry over 400,000 vehicles per day • 🔁 In certain areas, it expands to 18 lanes, making it one of the widest highways in North America The 401 is the backbone of transp