ORLANDO, Fla. – A record-breaking 112.5 million travelers—or more than one-third of Americans—will travel this holiday season, according to a forecast from AAA. That’s a 4.4% increase over 2017 and the most since AAA has been tracking holiday travel. 

An estimated 102 million people will pack up their cars for a holiday road trip, and INRIX, a global mobility analytics organization, warns that travel times in the most congested U.S. cities could take up to four times longer than normal.

“With a record-level number of travelers hitting the road this holiday, drivers must be prepared for delays in major metro areas, with Thursday, December 20 being the nation’s worst day to travel,” says Trevor Reed, transportation analyst at INRIX. “Our advice is to avoid traveling during peak commuting hours. If schedules allow, leave bright and early, or after the morning commute.”

While fuel has been relatively expensive this year, a recent drop in gas prices nationwide, along with more disposable income, is motivating many Americans to take to the highway for the holidays. In addition to auto travelers, 6.7 million people are expected to travel by air, a 4.2% jump over the same period last year.

The year-end holiday travel period is defined as the 11 days between Saturday, Dec. 22 through Tuesday, January 1, 2019.