CHICAGO (CBS) — If you’re getting out of Dodge for Memorial Day Weekend, you are definitely not alone.

AAA announced Tuesday morning that it estimates 37 million Americans – 60 percent more than 2020 – will travel for the holiday weekend.

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But we were wondering – how does the auto club come up with its predictions? CBS 2’s Lauren Victory took us inside their crystal ball.

The forecast is looking a lot sunnier for the official start of summer 2021. Memorial Day air travel is expected to be up almost 600 percent nationwide, according to AAA.

But the real talk of our town will be road trips. More than nine out of 10 Illinois residents who are planning getaways will jet off in their cars.

An estimated 1.7 million people from our state will hit the expressways between Thursday, May 27 and Monday, May 31.

Buckle up to hear how those numbers are calculated. It turns out it’s not as simple as an online survey or consumer phone calls.

AAA hires IHS Markit, an international research and analytics firm for each holiday forecast. The company does not ask the public about vacation plans – instead, an applied economics team crunches some serious data to predict them.

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“Big picture economic factors like overall economy growth, employment rates that all factor into the ability of consumers to travel,” said Shane Norton, a senior principal on the IHS Markit economics team.

Norton adds consumer confidence surveys, disposable income, and historical data are all used for the forecast as well.

“This year are some unique considerations we’ve had to take into account that don’t necessarily fit into economic fundamentals, so it’s been a bit of an extra challenge,” said Norton, who pointed to travel restrictions and unexpected COVID-19 surges.

Thanksgiving 2020 is a good example of a forecast that got a little wonky because of the pandemic.

Norton explains a virus spike hit after IHS Markit locked in its prediction of 50 million Turkey Day travelers, so the clarification, “…AAA expects the actual number of holiday travelers will be even lower…” had to be included in the forecast released to the public.

You’ll spot another caveat in the Memorial Day projections – vaccine confidence may lead to even more last-minute trips.

AAA expects gas prices will wind up at their highest levels in years compared to previous Memorial Day Weekends.

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That, along with lingering virus concerns and reduced capacity at theme parks and hotels may curb some demand this upcoming holiday. But with big-city mayors like Lori Lightfoot hoping to open up more by July 4, Norton expects Independence Day travel to be “massive.”

Lauren Victory