Mackinac Bridge Authority

Spanning the Straits of Mackinac since 1957

Frequently Asked Questions

Annual Bridge Walk

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For safety reasons, we do not allow banners, flags, umbrellas, or signs. We ask that you exercise good judgement for the safety of all who participate in this family orientated event.

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Visit www.mackinacbridge.org/walk to see current information about the Annual Bridge Walk.

Bridge Services

The Mackinac Bridge Authority (MBA) offers a bicycle transport service for riders and their bicycles, available 24 hours a day, seven days each week. The charge for this service is $15, which includes transportation for the rider and their bicycle. Masks are welcome, but not required, in MBA vehicles. No passengers under the age of 18 are allowed. Pickup locations are at Exit 339 (Jamet Street) for northbound travelers, and at the MBA administration building for southbound travelers. Call (906) 643-7600 to arrange for this service; calling ahead is recommended for large groups.

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Availability 24 hours a day, 7 days a week
Cost for service $10, plus the appropriate toll for the vehicle driven
To request from the north side Request the service from inside the administration building.
To request from the south side Pull over on the wide shoulder just north of exit 339 near the booth and call Bridge Services to request this service.

Drivers who do not feel comfortable driving across the Mackinac Bridge can have staff from the Mackinac Bridge drive their vehicle.  Drivers must be 18 years of age or older. The required liability waiver has been updated.

 

Facts

Answer:
There are two large finger joints at the towers to accommodate all the expansion of the suspended spans. There are 11 smaller finger joints and 5 sliding joints across the Mackinac Bridge. In addition, there are 13 expansion joints for the south viaduct spans – one for each of these simple spans. This adds up to a total of 31 total joints.

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The Mackinac Bridge is located in northern Michigan at the Straits of Mackinac. The bridge connects Michigan’s upper and lower peninsulas. Mackinaw City is located at the south end of the bridge. St. Ignace is located at the north end of the Mackinac Bridge.

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The height of the roadway at mid-span is approximately 200 feet above water level. The vertical clearance at normal temperature is 155 feet at the center of the main suspension span and 135 feet at the boundaries of the 3,000 ft. navigation channel.

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Although the Mackinac Bridge remained one of the four longest suspension bridges for more than 40 years, several bridges built since 1998 have surpassed it. Suspension bridges are commonly measured by main span length which is the distance between towers. By this ranking, the Mackinac Bridge is currently the twenty fourth longest suspension bridge in the world, and the third longest suspension bridge in North America. However, due to the Mackinac Bridge’s long side spans it remains among the top five longest suspension bridges in the world in suspended length; and the longest in the western hemisphere measuring 7,400 ft from bent pier to bent pier. The suspended length is the length by which the bridge deck is only supported by the cables. By total length the Mackinac Bridge, at 5 miles long, remains one of the longest bridges of its kind. By comparison, the Akashi Kaikyō Bridge in Japan, which is currently considered the longest suspension bridge in the world with a main span length of 6,532 ft, is less than 2.5 miles long in total length.

Figure 1. Suspension bridges are often ranked according to the main span length, which is the length between towers. However, the total suspended length of a suspension bridge can include its side spans.

 

Table 1. Common ranking of suspension bridges of the world by main span length

Table 2. Ranking of suspension bridges in the Western Hemisphere by suspended lengths.

 

 

Answer:
The steel superstructure will support one ton per lineal foot per roadway (northbound or southbound). The length of the steel superstructure is 19,243 feet. Each direction will, therefore, support 19,243 tons. The answer is 38,486 tons (2 x 19,243 tons).

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All suspension bridges are designed to move to accommodate wind, change in temperature, and weight. It is possible that the deck at center span could move as much as 35 feet (east or west) due to high winds. This would only happen under severe wind conditions. The deck would not swing or “sway” but rather move slowly in one direction based on the force and direction of the wind. After the wind subsides, the weight of the vehicles crossing would slowly move it back into center position.

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The width of the roadway is 54 feet. The outside lanes are 12 feet wide (2), the inside lanes are 11 feet wide (2), the center mall is 2 feet wide, and the catwalk, curb and rail width is 3 feet on each side – totaling 54 feet. The stiffening truss width in the suspended span is 68 feet wide making it wider than the roadway it supports.

Falling Ice

Since 1995 (as far back as we have records for partial and total closures), the Authority has closed the bridge 28 times for ice. The first noted closure was on Jan. 30, 1998, when the bridge was closed for two hours and 50 minutes. The most recent was April 3, 2022, when the bridge was closed for six hours and 57 minutes. There have been 28 falling ice closures in the past 27 years, or an average of about one each year. Falling ice closures usually happen in January, February, March, or April, though there have been a few in November and December over the years. They usually follow mixed precipitation or freezing rain events that coat the bridge, or when accumulated snow melts during the day, and freezes as ice at night.

Our friends at the National Weather Service found no increased frequency of freezing rain advisories or warnings around the bridge, though we are seeing more brief warmups during winter in recent years, which may be contributing to falling ice events.

The shortest closure was 37 minutes on Nov. 29, 2001. The longest closure to date was 20 hours and 15 minutes in a closure that started Feb. 23, 2019, and ended Feb. 24, 2019. The average closure lasts about five hours and 9 minutes. Over the last 27 years, which is roughly 236,520 hours, the bridge has been closed 144 hours and 39 minutes for falling ice (about 0.06 percent).

There’s really very little that can be done to prevent this type of closure. Like partial and full closures for high winds and blizzards, falling ice closures are the result of weather that is difficult to predict or prevent. Ice usually forms during freezing rain or mixed precipitation events on the upper main and suspender cables, or on the flat surfaces of the towers, typically in the later winter/early spring months. When temperatures rise or winds pick up, that ice is knocked loose and falls to the bridge deck several hundred feet below. Because there are no anti-icing or de-icing technologies on the bridge, Authority staff generally just need to wait until the ice has stopped falling (either because it has all cleared or temperatures have dropped and it stops falling) to reopen the bridge to traffic. To further complicate matters, the weather at the tower tops is different than the weather at the road deck. It can be colder up there, keeping the ice frozen longer and causing longer closures.

Some photos and videos have been included in a video about the dangers of falling ice on the Mackinac Bridge.

Falling ice is definitely dangerous and a hazard for people even when they are inside their vehicles. Sheets of ice as large as garage doors fall from the flat surfaces of the bridge towers, ice spears that form on the suspender cables fall straight down toward the bridge deck, and chunks that have formed on upper cables fall hundreds of feet (the tower tops are more than 300 feet above the roadway). Some of those pieces that have survived the fall are as large as a loaf of bread, and windshields and roofs have been caved in on both Authority and private vehicles. This is not a theoretical danger. Unless you have a telescope, it would be difficult to see the falling ice from the shore, but our staff gets as close as they safely can to monitor falling ice, and it’s definitely scary. You wouldn’t stand beneath your garage eaves when icicles were falling, would you? You certainly don’t want to be under this ice when it’s falling.

It’s not the paint, we’ve been assured by our painting contractors and other experts. Icephobic paint is certainly something we can explore for future painting, but that type of paint is currently only in the research stages for the aviation industry. The Authority recently completed a multiyear, multimillion dollar repainting project on the bridge towers (the first time those structures have been completely stripped and repainted since the bridge was opened in 1957). Painting the bridge cables is an ongoing process, so there is potential to introduce some paint advances in future work.

During past falling ice closures, maintenance staff has driven fully loaded plow trucks across the bridge to help shake ice loose. In very narrow circumstances, when the bulk of ice has formed on the underside of the main cables, steeplejacks have gone out onto the cables to knock ice loose. Often, however, surfaces are too slippery to safely allow maintenance workers out onto the cables.

Some type of heating system could be possible but running a current through the bridge could result in corrosion of some bridge components, and heat cables would be costly to install and maintain. Other methods, such as devices that “patrol” cables to prevent ice from forming, are being tried on other bridges, but would be difficult to retrofit to a bridge like the Mighty Mac. So far, the Authority has not found a cost-effective and practical solution relative to the infrequent, short-term closures resulting from falling ice, nor one that wouldn’t potentially damage the bridge. Icing is a problem for cable bridges around the world in climates like ours and no one has developed a practical solution to this infrequent but annoying problem.

We’ve heard many ideas to shake ice loose from the bridge, and while some of them might have some limited potential success, they also come with risks of damaging the structure. We’ve also heard some far more outlandish ideas: shooting it down (yes, with guns), using hair dryers attached to drones, or blasting the ice with tunes from Ted Nugent on an amplifier set to “11,” which we take as tongue-in-cheek suggestions. We’re willing to hear any and all ideas, but so far we’ve not found one that is safe and effective.

Not really. The Authority is currently saving up to replace the existing deck, at an estimated cost of several hundred million dollars, but it’s unlikely the current superstructure could support a second deck. Again, for the few times falling ice closes the bridge, and the relatively short duration of those closures, it wouldn’t be a cost-effective mitigation, even if it was possible.

Simply put, it’s because we don’t know when the bridge will reopen. Once ice begins falling from the towers or cables, shaken loose though higher winds or rising temperatures, it’s impossible to know when that will end. Sometimes closures end because the ice has melted and completely cleared; sometimes it’s because temperatures have dropped and the ice freezes back into place. We can and do look at weather forecasts and our own atmospheric equipment so we can alert our Twitter followers that conditions are likely to result in falling ice, as well as during closures to see when winds or temperatures are likely to fall (or rise), but the ice has a mind of its own and leaves at its own speed.

Please refrain from calling the Authority office for updates during a closure; until the bridge reopens, there will be no different information available.

The Authority website (www.MackinacBridge.org/conditions) is updated with current travel conditions for the bridge, including closures. Closure information is also posted on the Authority’s Twitter page, @MackinacBridge. People who are interested in receiving text messages about bridge closures can sign up for Mackinac County 911’s RAVE Alert System updates. There is no cost to receive these updates, aside from any texting fees from the participant’s mobile coverage plan. To opt into this text alert system, text “MacBridge” to 67283. The Michigan Department of Transportation (MDOT) also posts closure information on its network of dynamic message signs on both sides of the bridge, and local radio stations will share information about closures.

We try to stay in touch with customers during closures, but as we said, there aren’t a lot of updates that we can give aside from announcing the closure has ended. Predicting when that will occur isn’t something we can do.

While we certainly sympathize with being stuck in a closure of uncertain duration, the Authority isn’t equipped to aid travelers in that way. We do know from experience that the two communities have responded to the needs of travelers during past closures, though nobody likes to be unexpectedly delayed. We won’t pick favorites for local businesses to patronize, but there are great places to eat, fuel up, and be as comfortable as possible during the wait. In the case of longer closures, local schools and some churches have opened their doors as warming shelters.

We can’t, and won’t, allow non-emergency traffic across the bridge during a falling ice closure. We’ve seen up close the size and shape of the ice that falls from the towers and cables, as well as the damage it has done to vehicles over the years. A piece like that coming through your windshield from 300 feet up? Deadly. If a motorist was allowed to cross at their own risk and was struck by falling ice, Authority and emergency personnel would then be at risk responding to the situation. We know this is a dangerous situation, so there’s no waiver you could sign that would let us in good conscience allow you to risk it.

Not us, as we’re not a law enforcement agency, but our partners with local police departments and the Michigan State Police sure will. In fact, they’ve done it before, and those who have tried didn’t make it across. We urge you not to attempt it.

The Authority can’t be the arbitrator for what constitutes an emergency. If you approach our staff asking to cross due to an emergency, you are welcome to call 911, or they can do so for you, and law enforcement officers can (as appropriate) take the necessary steps to get you across for your emergency situation.

History

Answer:
The French pronounced it “aw” but spelled it “ac”. The British heard it pronounced “aw” so they spelled it that way. Whichever way you see it spelled, it is always pronounced “aw”.

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Mackinac is Canadian French, short for Michilimackinac, from early Ojibwa “Missilimaahkinaank” which means “at the territory of the Mishinimaki”. The Mishinimaki was an extinct division of the Ojibwa formerly living in this region.

All of the general information that we formerly sent out by mail has been placed on our web site for your convenience. Please browse through our various menu items such as facts and figures, the photo gallery and the history pages. You are welcome to download pictures from our web site to use in your report.

Answer:
There are no bodies buried in the concrete supports of the Mackinac Bridge. Five workers died during the construction of the Mackinac Bridge. One died in a diving accident; one fell in a caisson while welding; one fell a couple of feet into the water and drowned; and two fell from a temporary catwalk near the top of north tower. All but one body was recovered. When the two workers fell from the temporary catwalk, they fell approximately 550 feet. One body was recovered immediately. A three-day search for the other worker ended without success.

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Five men died during the construction of the Mackinac Bridge. The names of the five workers and dates of death: Frank Pepper, September 16, 1954; James R. LeSarge, October 10, 1954; Albert Abbott, October 25, 1954; Jack C. Baker, June 6, 1956; and, Robert Koppen, June 6, 1956. Information about the five workers who died during construction of the Mackinac Bridge can be found in Mr. Larry Rubin’s book titled “Bridging the Straits”.

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Bonds ($99,800,000) for the project were issued in early 1954. The proceeds to the Authority amounted to $96,400,033.33. The cost to design the project was $3,500,000 (Steinman Company). The cost to construct the bridge was $70, 268,500. Two primary contractors were hired to build the bridge: American Bridge for superstructure – $44,532,900; and Merritt-Chapman and Scott of New York for the foundations – $25,735,600. The remainder of the proceeds from the bond sale was used to service the bond debt both during and after construction. Tolls could not be collected until the bridge was opened to traffic on November 1, 1957.

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The bridge was opened to traffic on November 1, 1957.

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Michigan has two peninsulas – the Upper and the Lower. The closest point between the peninsulas is the Straits of Mackinac – approximately 4 miles in length. Because of the distance and difficulty to get back and forth, people were interested in improving transportation and commerce. In 1923, the State Highway Department started ferry service in the Straits area in response to demand for service. Ferry boats were very popular and the demand increased. In the last year of operation, the ferries transported 900,000 vehicles. The ferries couldn’t keep up with the demand. It proved that if you provided a connection, people would use it.

Miscellaneous

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The Bridge at Mackinac

In the land of Hiawatha,
Where the white man gazed with awe
At a paradise divided
By the straits of Mackinac

Men are dredging, drilling, blasting,
Battling tides around the clock,
Through the depths of icy water,
Driving caissons down to rock.

Fleets of freighters bring their cargoes
From the forges and the kilns;
Stones and steel – ten thousand barge-loads –
From the quarries, mines, and mills.

Now the towers, mounting skyward,
Reach the heights of airy space.
Hear the rivet-hammers ringing,
Joining steel in strength and grace.

High above the swirling currents,
Parabolic strands are strung;
From the cables, packed with power,
Wonder-spans of steel are hung.

Generations dreamed the crossing;
Doubters shook their heads in scorn.
Brave men vowed that they would build it –
From their faith a bridge was born.

There it spans the miles of water,
Speeding millions on their way –
Bridge of vision, hope and courage,
Portal to a brighter day.

Answer:
The live camera picture of the Mackinac Bridge is a very popular feature of our site and others. The Mackinac Bridge currently has 4 cameras. The cameras show the views from the Mackinac Bridge administration building looking south, the Mackinac Bridge dock in St. Ignace looking south, the Bridge View Park in St. Ignace looking south, and one in Mackinaw City looking north.

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The live camera picture of the Mackinac Bridge is a very popular feature of our site and others.  The camera images are configured to automatically update every 60 seconds. The time stamp indicates the last captured image. If your browser does not display the most recent image, you may need to refresh the browser.

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To get a side profile schematic, try contacting Errolgraphics Inc., P.O. Box 40800, Portland, Oregon 97240. They produced a side schematic in 1997. Their web site is www.errolgraphics.com.

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For travel information, We recommend that you contact agencies such as Pure Michigan, the Mackinaw City Chamber of Tourism, the Mackinaw Area Visitors Bureau, the St. Ignace Chamber of Commerce, and the St. Ignace Visitors Bureau.

 

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For information about Michigan, visit the Pure Michigan website.