The roughly 70-mile-wide path of totality — where the moon will block 100 percent of the sun — stretches from Oregon to South Carolina.
In Oregon, where the totality begins at 10:16 a.m. at Depoe Bay, officials have ordered extra-wide-load trucks off the highways through Tuesday to ease congestion, and in Madras, Ore., which has been identified by many experts as one of the prime viewing locations, the National Guard is being called in to help control traffic. The event ends 92 minutes later outside McClellanville, S.C., where the state is bracing for more than 1 million visitors.
"Basically we'd all be on the phone and we'd go west to east around the group in the conversation and compare notes and bring up concerns, and then a lightbulb would go off in someone's head. And we basically kept doing that until we felt we were completely prepared," said Matt Hiebert, assistant director of communications at the Missouri Department of Transportation.
Hiebert, who chaired the task force of state highway officials, said they agreed on a common message and communication strategy to educate the public. One of the biggest concerns: motorists stopping on the interstate or shoulder to view the eclipse, which in addition to being a safety hazard would cause massive gridlock.
The Federal Highway Administration has asked states to suspend all road construction Monday to ease the flow of traffic. FHWA also is changing interstate dynamic message boards nationwide: A total solar eclipse is coming. The sky will get dark. The sun will appear to go away in the middle of the day. Do not slam on your brakes. Do not be afraid.
"We don't really know exactly how many might be out there driving around . . . but we know that there will likely be several million," said Martin Knopp, associate administrator for operations at FHWA.
In most states, it's an "all hands on deck" situation for highway workers and law enforcement and they will be out in force to both keep traffic moving and help motorists who might need assistance. From there, "each state works a little differently," Hiebert said.
In Missouri, for example, the eclipse coincides with the end of the state fair on Sunday and the first day of classes for Missouri State University on Monday. Highway work zones have been suspended in key areas to ease traffic flow, but they can't ban wide-load trucks when there are roller coasters and other fair rides to break down and move out.
The eclipse will reach its point of greatest duration in Carbondale, Ill., and officials there have a "bring it on, we're ready" attitude when it comes to visitors, Hiebert said. But once all those people arrive where do you put them?
Carbondale officials are asking visitors — estimated to be around 70,000 — to park outside the city.
"One of the key strategies we developed . . . is to establish remote parking areas on the periphery," City Manager Gary Williams said. The city has contracted with a local bus company to shuttle passengers to and from downtown.
State officials estimate 100,000 to 200,000 people will visit southern Illinois for its prime viewing locations and they've suspended most road construction starting Friday morning and continuing through Tuesday evening.
Eventually, all those visitors will return home, which means they will need gas.
Aimee Inama, a spokeswoman with the Wyoming Department of Transportation, is an East Coast native. She points out that drivers from that part of the country are used to cities — and gas stations — being a lot closer together.
"Out here, there's not a lot of cities between cities," she said, "so we're really urging motorists to make sure they have plenty of fuel. Stop, fuel up as often as you can, because sometimes there's miles and miles of road that there's no cities in between."
On a normal Monday, you can stand in the middle of Kentucky Highway 624, outside Hopkinsville city limits, and not see a single car. To the right, Mary Jane Cornelius's soybean field goes on for acres. At the end of the road — where 624 meets Kentucky Highway 91, you'll find three houses: Doug Mosley lives in the middle with his son and daughter on either side. Once a day, he comes out to check the mail. Otherwise, you're unlikely to see anyone.
On Monday, "That [intersection is] essentially Ground Zero for the whole country," said Keith Todd, a spokesman for the Kentucky Transportation Cabinet.
A curve in Kentucky 624 here is the point of greatest eclipse.
The town of 32,483 people is prepared for about 100,000 visitors from 36 states and 14 countries, according to Brooke Jung, Hopkinsville Solar Eclipse marketing and events coordinator.
Ten miles northwest, across the road from Cornelius's soybeans, 176 members of the press, up to 700 general admission tourists, and approximately 50 invited VIPs (including Sens. Mitch McConnell and Rand Paul) will convene.
"We're dumping a large amount of people in rural, sparsely populated areas with little to no infrastructure," said Capt. Brent White of the Kentucky State Police. The post White oversees includes Hopkinsville and Interstate 24, one of 20 interstates FHWA has labeled a point of concern.
"We expect some gridlock, but we're gonna try to keep the traffic free-flowing. . . . We don't want these areas to turn into parking lots," White said.
Hopkinsville's emergency management director, Randy Graham, has partnered with around 150 different organizations, including KSP. Hopkinsville is along the Kentucky-Tennessee border, so these meetings included talks with Tennessee Highway Patrol. The two police organizations will monitor state-line traffic, alerting each other to what's coming.
In 2011, Kentucky Speedway hosted its first NASCAR race. The track's designers only built enough parking to accommodate ticket-holders, not realizing fans without tickets tailgate. More than 20,000 cars created a day-long bottleneck on I-71, blocking traffic as far as Louisville's Watterson Expressway 52 miles away.
"We may have the very same issue with people trying to come up Kentucky 91 to get in a farm field that's been designated [for parking] that's all full," White said. "One thing that I fear is that they'll get to Hopkinsville and try to get in those public access areas there and as they fill up, they will keep driving north until they find something and that something may not be there."
Todd notes parking also caused Woodstock's traffic woes in 1969: "Between 500,000 and 600,000 people went to that event. You had people stopping their cars in the travel lane of the New York State Thruway, abandoning their vehicles and walking 30 miles to get [there]."
In an area this rural, there's no shortage of fields that theoretically could have offered parking. But local farmers need that land to make a living. David and Becky Ginn have cleared 75 acres for a Christian tent revival with free camping and parking. In addition to the eclipse traffic, Becky Ginn says the revival will draw 5,000 to 6,000 people, adding further strain to two-lane 91.
"To a certain extent, it would be easier to handle traffic control if everybody were going to one particular point, like a stadium," Todd said. Yes, there are 200 million who live within a day's drive of the totality, but no one knows how many will drive to Oregon versus Idaho; St. Joseph versus Marshall, Mo.; Hopkinsville versus Carbondale, Ill.
Eddie Prevette oversees dispatch for Max Arnold & Sons, a Kentucky-based convenience store chain. It's his job to make sure gas gets to 45 different MaxFuel, Marathon and BP stations within the totality.
"Our storage tanks at our stores — and our competitors' stores . . . were built for what our current demand is," he said. Right now, there's a Pepsi trailer outside MaxFuel's flagship location so the store won't run out of drinks. But with gas, you can't do that: Fuel tanks are buried underground.
"Stores that get a delivery every two days [are] going to get possibly two loads in one day," Prevette said. "Other stores maybe where they get a load every three days, they may have to have a load every day during this eclipse [weekend]."
More fuel trucks on the road means even more traffic. It's the eclipse's own chicken and egg problem: Yes, fuel haulers will cause more congestion, but gas companies have to make the problem worse before they can make it better. Cars with empty tanks would clog roads far more.
Of course, if they're delivering gas, it's easy to understand why some trucking companies need to haul on Eclipse Day. But what about products like dishwashing liquid and paper towels? Those are the type of products Walmart routes through its Hopkinsville distribution center, less than three miles from the I-24 off-ramp. On a normal day, freight trucks make roughly 10 percent of Kentucky traffic.
FHWA has asked freight haulers with nonessential cargo to stay off highways Monday, but the decision is ultimately up to the haulers and their customers.
Walmart's corporate headquarters did not respond to several requests for comment, but Barbara Dulin, human resource manager at the Hopkinsville distribution center, said: "We're staying open."
Since eclipse chasers will trickle in over the weekend, road restrictions started early and will last past Monday. Extra-wide-load trucks aren't allowed on Oregon roads through Tuesday; overweight and oversize vehicles are prohibited in Wyoming through Tuesday too. Similar bans or warnings have been issued in Idaho, Nebraska, Missouri and South Carolina.
The eclipse is not expected to impact air or rail travel, in fact officials are encouraging any mode of travel that takes people off the roads.
On Monday, Hiebert and his counterparts will activate their respective emergency operations centers — similar to what they do during snowstorms or floods. They'll monitor road conditions and traffic flow, work with the media to get out updates and alerts, and stay in close touch with each other. They'll watch to see what happens in Oregon, the first state, for example, then make any adjustments to their own plans based on that if needed. The same will happen as the event moves through Idaho, Montana, Wyoming and so on. Officials will learn and adjust as the eclipse moves across the country.
"We're ready," Hiebert said.