Thursday, Dec. 20, was the nation's worst day for congestion overall.
“Our advice is to avoid traveling during peak commuting hours. If schedules allow, leave bright and early or after the morning commute,” INRIX analyst Trevor Reed said.
Approximately 6.7 million people will be traveling by air this year, the most in 15 years.
About 3.7 million Americans will use trains, buses and cruise ships to travel this end-of-year holiday season.