The Blue Water Bridge crosses the St. Clair River, connecting the communities of Point Edward/Sarnia, Ontario to Port Huron, Michigan. The Blue Water Bridge connects Highway 402 in Ontario with I-94 in Michigan, which provides south westerly access to Macomb County and the following Metropolitan areas: Detroit, Michigan; Gary, Indiana; Chicago, Illinois; Madison, Wisconsin; and Minneapolis, Minnesota. The Blue Water Bridge also provides access to Indianapolis, Indiana via I-69, and to St. Louis, Missouri via I-94 and I-55.

Since the Blue Water Bridge was opened, the traffic volumes have grown from approximately 155,000 total vehicles in 1939 to approximately 5.5 million total vehicles in 1999.

An average of 14,000 vehicles per day cross the Blue Water Bridge with as many 20,000 vehicles crossing on a busy day. As many as 6,000 trucks may cross the bridge on a heavy day.

The Blue Water Bridge is an essential economic link between Ontario and Michigan as well as a wider economic corridor through the United States and southerly to Mexico. The importance of the Blue Water Bridge as a major traffic/economic link between Canada and the United States, as well as between Ontario and Michigan, is demonstrated by the following statistics:

• Approximately 42% of all Canada-United States trade flows through the Michigan - Southwestern Ontario Frontier Gateway, of which approximately 74% is moved by trucks.
• Total traffic growth across the Ontario-Michigan border grew by approximately 85% between 1984 and 1998.
• Truck traffic growth across the Ontario-Michigan border grew by approximately 167% between 1984 and 1998.
• Passenger vehicle traffic growth across the Ontario-Michigan border grew by approximately 72% over the same period.
• Canadian exports to the United States, as a whole, reflect an annual growth of 6.2% between 1988 and 1995.

The Blue Water Bridge currently ranks as the fourth busiest Ontario international crossing for total vehicles and is the second busiest for number of commercial vehicle (truck) crossings. The Blue Water Bridge has experienced a substantial increase in commercial vehicle traffic from approximately 450,000 vehicles in 1984 to approximately 1,500,000 in 1999.