Be prepared for soul-crushing traffic jams this weekend into early next week thanks to Monday's solar eclipse. The U.S. Department of Transportation estimates nearly two-thirds of the nation’s residents live within a day’s drive of the path of totality.
This is the first coast-to-coast solar eclipse since 1918, making it difficult for transportation officials to prepare.
Oregon, the first state to view the eclipse, and Washington are expecting the worst traffic jams.
"This is the biggest transportation event that has ever hit Oregon," Dave Thompson, a spokesman for the Oregon Department of Transportation told AP.
Officials are urging commuters to telecommute or adjust work around the eclipse and festivities. More than 150 events are planned throughout Oregon and most hotel and campgrounds are completely booked.
The Idaho Transportation Department has placed around 20 traffic counters along interstates and highways in the Gem State to gauge how many drivers will be on specific roads at a time. This information will be used to direct the public to the best routes early next week.
AAA is expecting 6,000 roadside issues a day throughout the weekend and early next week, like flat tires, between Idaho and Oregon.
Wyoming could see as many as 600,000 visitors for the eclipse — more than doubling the state's population. If two-thirds of those visitors come from the south, that would mean an influx of 400,000 people on Colorado’s already-clogged highways. And that’s not including people making their way to Nebraska through Colorado.
“We are fully expecting that every single road going up into Wyoming or Nebraska is going to be packed,” Colorado Department of Transportation spokesman Jared Fiel said.
Fiel said traffic will be worse on the return journey — heading south from Monday afternoon to Tuesday morning — as opposed to the days leading up to the eclipse, when the rush will be more dispersed.
CDOT is hitting the pause button on all road construction from Friday afternoon to Tuesday morning, and oversize and overweight vehicles (think semi-trucks, not RVs) won’t be allowed to travel through most of Colorado through Wednesday morning.
CDOT and Colorado State Patrol officers will be stationed at various locations around Northern Colorado so they can respond quickly to crashes and other emergencies.
To make matters worse, the eclipse traffic hits during a time many students, including those at Northern Colorado University and Colorado State University, are heading back to school.
The Illinois Department of Transportation, expecting up to 200,000 visitors, will eliminate most of its construction lane closures between Friday evening and Tuesday morning. They are advising drivers to turn on their headlights if they are driving during the eclipse.
Traffic in western Kentucky, expecting half a million visitors, could be particularly tricky in part because of the U.S. 41-twin bridges. Henderson County Emergency Management Director Larry Koerber said even though police will be stationed there, he's concerned a possible crash on the bridges could choke the roads "for hours."
Message boards will be used along roadways to keep motorists informed of possible delays.
"We are thinking about what could happen. Anticipating some things, but realistically, it's going to be reactive and not proactive," Koerber said. "We can't anticipate everything."
The state of South Carolina could see up to 2 million people, state officials said. Greenville County, S.C., alone expects anywhere from 400,000 to 500,000 visitors jamming roads through Wednesday. Hotels are completely booked Sunday night, said Capt. Damon Hubber, director of the county's Office of Emergency Management. At least 46 eclipse-related events are planned in the area Monday, which could encourage visitors to stay more than just one night.
The U.S. Department of Transportation is urging drivers not to stop along the interstate or park on the shoulder of a road during the eclipse, never take photos while driving and prepare for extra congestion around the event.
Contributing: The USA TODAY Network and The Associated Press. Follow Ashley May on Twitter: @AshleyMayTweets