Americans couldn’t resist the urge to gather for Thanksgiving, driving only slightly less than a year ago and largely ignoring the pleas of public health experts, who begged them to forgo holiday travel to help contain the coronavirus pandemic, data from roadways and airports shows.

The nation’s unwillingness to tamp down on travel offered a warning in advance of Christmas and New Year’s as virus deaths and hospitalizations hit new highs a week after Thanksgiving. U.S. deaths from the outbreak eclipsed 3,100 on Thursday, obliterating the single-day record set last spring.

Vehicle travel in early November was as much as 20% lower than a year earlier, but it surged around the holiday and peaked on Thanksgiving Day at only about 5% less than the pandemic-free period in 2019, according to StreetLight Data, which provided an analysis to The Associated Press.

“People were less willing to change their behavior than any other day during the pandemic,” said Laura Schewel, founder of StreetLight Data.

Airports also saw some of their busiest days of the pandemic, though air travel was much lower than last year. The Transportation Security Administration screened more than 1 million passengers on four separate days during the Thanksgiving travel period. Since the pandemic gutted travel in March, there has been only one other day when the number of travelers topped 1 million — Oct. 18.

“If only a small percentage of those travelers were asymptomatically infected, this can translate into hundreds of thousands of additional infections moving from one community to another,” Dr. Cindy Friedman, a Centers for Disease Control and Prevention official, said this week during a briefing.

Wide swaths of the country saw a sudden influx of people arriving from university campuses in the days leading up to the holiday, according to a data visualization of anonymous cellphone data from a firm called Tectonix.

The Centers for Disease Control and Prevention has urged people to stay home for the holidays, but officials acknowledged that many people would not heed that advice and advised them to get tested before and after trips. Friedman said that this year’s holidays presented “tough choices” for many families.

The travelers included some elected officials who preached against trips. The mayors of Denver and Austin, Texas, faced fierce backlashes for traveling after telling other people to stay home.

Others had no regrets. Trananda Graves, who runs a travel-planning company in Keller, Texas, took a Thanksgiving road trip with her family to Nashville, Tennessee. It was a chance for her daughter to connect with relatives as they shared recipes, and Graves said everyone’s mood was uplifted.

“It was just a break to get away from home,” Graves said. “We work at home, we go to school at home.”

She decided to drive to meet extended family after seeing that flights were crowded and said her family followed guidance to avoid spreading infections.

But infections, even from small Thanksgiving gatherings, have begun to stream in around the country, adding another burden to health departments that are already overwhelmed.

“This uptick here is really coming at a time when everyone’s exhausted,” said Don Lehman, a spokesman for the Warren County Public Health Department in upstate New York.

The county concluded that Thanksgiving gatherings or travel likely caused 40% of the 22 cases it reported in the last two days. That means contact tracers have to figure out where people came from or traveled to and contact health officials in those places. Lehman said it adds “a lot of legwork” to the contact-tracing process.

Graves said she expects an uptick in the travel-planning business around the holidays. Several groups have already inquired about going to Las Vegas to celebrate the end of an arduous year.

And her personal holiday plans? After the Thanksgiving trip, she said, “Now we are considering visiting my mother for Christmas.”