Monday's total solar eclipse will be the first to slice across the US in 99 years, inspiring many Americans to pack up the car and drive to totality: the path of the moon's darkest shadow.
In fact, up to 7.4 million people may journey to the 70-mile-wide, 2,800-mile-long track where the moon will block the sun and reveal the star's wispy corona.
That's according to Michael Zeiler, a cartographer at Esri, a mapping data and technology company.
Zeiler has anticipated this moment since he started chasing eclipses 26 years ago. He has spent the past few years gathering data, plotting maps of the eclipse (and its surprising ramifications), and uploading them to his website, GreatAmericanEclipse.com.
Zeiler considers his "driveshed" maps some of his favorites. Like watershed maps that show how brooks, streams, and rivers move toward an ocean, his version shows where vehicles are most likely to flow toward a viewing location.
"I thought about about every populated point in the United States, and I asked the data: What is the quickest drive to totality?" Zeiler told Business Insider. "I discovered there's going to be about one or two dozen traffic-congestion points that are going to be particularly severe."
Here are the 12 biggest drivesheds Zeiler has identified, the cities they center on, and — by extension — the places most likely to be choked with gridlock traffic.
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Zeiler's "drivesheds" maps show the routes that drivers are most likely to take.
Zeiler said he had given several presentations and seminars on these maps, including one to the American Association of State Highway and Transportation Officials, or AASHTO.
The maps are based on another analysis he did that shows how close Americans are to the path of totality and how long it would take to make the journey to it.
12. Columbia, South Carolina — 5.5 million people in range
Zeiler says that if you are driving to the path of totality, be sure to leave at least a day early, on Sunday, and plan to wait for traffic to clear for several hours after totality ends.
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