Architecture: The Detroit-Windsor Tunnel


Well, after being stranded here in New York for the past few days, I am leaving tomorrow for Detroit, my hometown. Detroit has a lot of great architecture and I wanted to blog about something that is truly Detroit. One of my fondest memories as a kid was when my parents would take us to Canada for the day to shop. Back when I was a boy, the U.S. dollar was worth a $1.25 in Canadian currency, so I was able to get more for my money. I loved driving through the tunnel listening to CKLW on the radio (the only station that could be played in the tunnel). My brother and I would always wait for the exact moment where you left the United States and entered Canada (see photo below).

So, I am blogging about one of the greatest engineering feats of all time. I hope you find it as exciting as I do.

Best Regards,



Point of international crossing is marked

The Detroit-Windsor Tunnel

The magnitude of the Detroit-Windsor Tunnel job is well indicated by the following figures relative to the work performed and the quantities of materials used in the construction of the mile-long tube:

Total excavated material yards 525,000 cubic yards
River excavation 275,000 cubic yards
Weight of excavated material 787,500 tons
Concrete poured 80,000 cubic yards
Reinforcing steel used 750 tons
Total structural steel 11,000 tons
Lining for shield-driven sections 3,900 tons
River tubes 3,550 tons
Electrical conduits 50.5 miles
Roadway area 4 acres
Granite blocks in original roadway 2,000,000
Wall area 2.5 acres
Number of wall tiles 250,000
Lights in tunnel 574
Welding 12 miles
Depth of mud over tunnel 4 to 20 feet
Maximum depth of water 45 feet
Maximum depth of trench 50 feet
Maximum depth of roadway 75 feet
Length of tunnel 5,160 feet
Length of river section 2,200 feet
American shield-driven section 1,243 feet
American approach 627 feet
Canadian approach 600 feet
Cost $23,000,000
Width of roadway 22 feet
Traffic capacity per hour 2,000 vehicles
Maximum number of laborers employed simultaneously 600

More quick facts…

  • The Tunnel was finished a year ahead of schedule at a total cost of $23 Million.
  • The Detroit-Windsor Tunnel was formally dedicated on Saturday, November 1, 1930. President Herbert Hoover turned a “golden key” in Washington that rang bells in both Detroit and Windsor to mark the opening of the tunnel.
  • The Tunnel is jointly owned by the Cities of Windsor, Ontario and Detroit, Michigan.
  • It is operated under two separate agreements by the Detroit and Canada Tunnel Corporation.
  • Approximately 12,000 vehicles pass through the Tunnel on a daily basis, handles almost nine million vehicles per year, of which 95% are cars and 5% are trucks.
  • Ventilation – 1.5 million cubic feet of fresh air is pumped into the tunnel each minute.
  • Renovations: A $50 Million renovation program was launched in 1993, including a completely new road surface, new sidewall tiling, new lighting, complete video surveillance and restoration of the Tunnel’s stone cover beneath the Detroit River.

Did you know that the Detroit-Windsor Tunnel is the only existing sub aqueous international vehicular border crossing?

That means it is the only underwater-tunnel that crosses International borders in the entire world!

The tunnel has been recognized as one of the great engineering wonders of the world.


As you travel almost a mile, 75 feet below the surface of the Detroit River, you’re surrounded by 574 lights, 80,000 cubic yards of concrete, and 750 tons of reinforced steel.

The Tunnel has 4 acres of roadway area and one of the most elaborate ventilation systems ever devised.

Located between Detroit, Michigan and Windsor, Ontario, The Detroit Windsor Tunnel connects the U.S. Interstates to Ontario’s Highway 401. It is a large complex consisting of toll and inspection plazas on each side of the Windsor-Detroit border where you pay for your crossing and undergo inspections by Immigration and Customs.

The Tunnel provides one of the fastest links between Canada and the United States.


U.S. Customs and Protection Checkpoint

How long is the Tunnel?

The Detroit-Windsor Tunnel is approximately one mile long from portal to portal. The American portal is located a few hundred feet from Downtown Detroit while the Canadian end is located in the heart of Windsor’s business district.

The Tunnel is 5,160 feet long (1,573 meters) with a height clearance of 13 feet 2 inches (4 meters). The roadway is 22 feet wide (6.7 meters) and allows for two lanes of traffic in opposite directions. The maximum depth of the roadway beneath the river surface is 75 feet (22.8 meters).


Entering from the American side at Jefferson Ave.

When did the Tunnel open?

The Tunnel first opened to traffic on November 3, 1930. Construction took 26 months and cost $23,000,000. Promotion of the Tunnel started over 120 years ago.


Entering from the Canadian side at Goyeau Street.

Tunnel Construction History

The Detroit-Windsor Tunnel was the first vehicular subway ever built between two nations. At the time of its construction, two other tunnels were in use in the United States — the Holland Tunnel in New York and the George A. Posey Tunnel connecting Oakland and Alameda, California.

Detroit-Windsor Tunnel

As early as 1870, Detroit citizens were greatly debating the relative merits of a bridge and a tunnel between Detroit and Windsor. The railroads favored a bridge while shipping interests felt that a bridge structure would be hazardous to navigation, due to the exceedingly high masts of the sailing ships that forged the Detroit River at that time.

A Route for Swift, Border Transportation is Born

Attention then turned to a tunnel project as a means of providing swift transportation across the river. In 1871, ground was broken near the foot of St. Antoine Street for a tunnel under the Detroit River. It was to have a 15-foot bore, surrounded by masonry.

However, a pocket of sumptuous gas ended the project when workers were 135 feet out under the river. The gas made the workers so sick that none of them could be induced to resume work on the following day. The project was abandoned.


Detroit portal of the tunnel

Detroit’s second tunnel venture took place in 1878, when a tube was proposed to connect Grosse Ile, Michigan with the Canadian mainland. No gas was encountered, yet this undertaking had to be abandoned because certain limestone formations made the cost of excavation prohibitive. In 1874, the Detroit Board of Trade made a determined effort to promote a bridge, despite the opposition of shipping interests. Nothing came of this project.

When the Grand Trunk Railway Tunnel under the St. Clair River at Port Huron opened in 1891, this caused another flurry of activity about additional tunnel construction. This railway tunnel was 6,000 feet in length and at the time was the longest, sub aqueous tunnel in the world. Detroit business interests, afraid of a diversion of shipping to Port Huron, made a desperate effort to generate public support for a tunnel in Detroit.

In 1906, construction began on the Michigan Central Railway Tunnel in Detroit and was completed four years later. It had a total length of two and one-half miles and cost $8,500,000. However, the opening of this tunnel did not lessen the agitation for vehicular transportation facilities across the Detroit River, especially after the phenomenal growth of the automobile industry. Bridge and tunnel advocates remained active in support of their respective undertakings, culminating several years later in an announcement that Detroit would have both projects.

In June 1919, Windsor’s Mayor Edward Blake Winter requested Ottawa to construct a tunnel as a memorial to soldiers who died in World War I. Winter’s argument was that a tunnel between England and France had been proposed as a war memorial, and if England and France could be united by a tunnel, so should Canada and the United States.

Despite the opinion of scientific experts that anyone using the tunnel would die of carbon monoxide poisoning, a Windsor Salvation Army Captain, Fred W. Martin, pursued the dream of a Detroit-Windsor tunnel. It was not until 1926, when a prestigious, New York architecture firm predicted that a tunnel would not only be feasible but profitable, that Martin found enough backing to get the project underway. A group of Detroit bankers agreed to back the project provided that the New York architects would design the tunnel and guarantee its construction costs.

Construction Begins

Construction operations began in the summer of 1928 at approximately the same time on both sides of the river. The completion of the tunnel was an engineering feat unparalleled at the time, which combined three different tunneling methods.

On each side of the river, a cut and cover method was used on the sections from where the open cut trenches end to the harbor line. Earth was dug away by muckers or sandhogs that used manually operated knives to cut a path for the giant, shield wall.

Detroit-Windsor Tunnel Construction

As the shield moved forward, foot by foot, electrically welded steel plates were put in place behind it to form the tunnel tube. Construction of the river section of the tunnel was the most spectacular of the operations, as it involved sinking nine steel tubes into a trench dug across the bottom of the river.

The steel shells were built on dry land, welded watertight, sealed and floated into the river. Once they were tugged and anchored into position over the trench, the final interior and exterior concrete was poured, and the tubes were sunk and joined together by divers using a collar of tremie cement. Once the tube was in place, the trench was backfilled with 20 feet of material to hold it in place.

Detroit-Windsor Tunnel Construction

Meanwhile, the crews drove the shield section toward the tube, traveling underground 466 feet on the US side and 986 feet on the Canadian side, changing courses both vertically and horizontally. When contact with the submerged tube was made, there was less than one-inch error in alignment.

Breathe Easy in the Tunnel

The Tunnel has one of the most elaborate ventilation systems ever devised.

Detroit-Windsor Tunnel History

Ventilation towers are located at each end of the tunnel. Each tower is approximately 100 feet high, on a site 50 × 90 feet. Each tower, with its equipment, provides ventilation for half of the tunnel.

The equipment consists of motor-driven, fresh-air fans and exhaust fans arranged in successive tiers in different stories, with direct connections to the fresh-air ducts in the tunnel. Each fan is 12 feet in diameter and each building houses 12 fans; six blower fans to draw in fresh air and six fans to expel used air and automobile emissions.

Detroit-Windsor Tunnel Construction

The total amount of fresh air that can be supplied to the ducts of the tunnel is approximately 1,500,000 cubic feet a minute. Fresh air comes into the tunnel under the roadway through apertures near the curb. Used or vitiated air is thrown off through two rows of openings located at frequent intervals in the ceiling.

While the fresh air is drawn into the ventilation buildings, the vitiated air is expelled through exhausts located at the top of each building.

The safety factor of the tunnel is so great that there is no possibility of the air becoming gaseous even if most of the fans were to stop functioning.

The ventilating system is patterned after that in the Holland Tunnel in New York.

Cross the Windsor-Detroit Border through The Detroit Windsor Tunnel, and you can be a part of history!



[1] The Detroit-Windsor Tunnel Official Website,

[2], Detroit-Windsor Tunnel,

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