Researchers have found Americans are venturing out of their homes more for the first time since social distancing guidelines were put in place in mid-March, despite warnings from experts strongly encouraging people to practice social distancing.

Led by Lei Zhang, director of the Maryland Transportation Institute at the University of Maryland, researchers have been tracking smartphone data to determine how well more than 100 million people are complying with stay-at-home orders. For six weeks, the percentage of people who were staying at home – meaning their phones moved less than a mile each day – increased or stayed the same.

On Easter Sunday, the number of people staying home reached a record high, Zhang told USA TODAY. But on April 14, one day before thousands protested quarantine measures at Michigan's Capitol, that number started to drop.

After "almost two weeks, it has been consistently dropping across the country," Zhang said. "Now for many states the level of their social distancing right now is about the same as the week of March 20th."

Zhang's team developed a social distancing index which scores states and counties on a scale from 0 to 100 based on factors including the percentage of people staying home, the number of trips on average people make, how many miles people travel, and travel outside the state or county. A 10 point reduction in the index is equivalent to 10% fewer people staying home, Zhang said.

Nationwide, the index decreased from 52 to 44. Every state except for Rhode Island saw a decrease in social distancing, according to Zhang. The ten states with the largest drop in their social distancing index as of April 24 were: Louisiana, Ohio, Indiana, Vermont, Alabama, Michigan, Missouri, North Carolina, Texas and Arkansas.

Thomas Walle, CEO of Norwegian company Unacast which collects and analyzes location data from various sources, has also been using smartphone data to track how well Americans are complying with stay-at-home orders. He said his social distancing scoreboard shows a similar drop in distance traveled around Easter and then a spike in both distance traveled and the number of devices in the same location in recent days.

"This is an early indication that we need to follow in the days and weeks to come of people having a fatigue," Walle said. "You can definitely see that there's starting to be a little trend here that people are more outside and less at home."

How well are we social distancing?:Smartphone location data can rank the states

After a month of quarantine, Zhang said a combination of warmer weather, a false sense of security of the flattening curve and discussion of reopening the economy in some states are likely driving people's desire to leave their homes. He said some people who have seen his data have reached out to say that although they know social distancing is important, they have to get back to work.

"For a lot of us there is some quarantine fatigue, but for others maybe it's more for economic reality kicking in," he said.

Zhang said his team is working with epidemiologists to put their data into models to predict future trends, but they won't be able to see the impact on COVID-19 cases and deaths for 1 to 2 more weeks. He added that public health officials he works with are concerned about the new trend.

Thomas Russo, professor of medicine and chief of the division of infectious diseases at the University at Buffalo, who was not involved with the study, said he was concerned but not surprised that people are starting to buck social distancing guidelines.

Russo said widespread testing is necessary to keep the outbreak contained as people become less compliant with social distancing guidelines. He added that public health measures including social distancing, wearing masks, hand washing are the only way to curb the spread of coronavirus.

"If we let up on those measures I think it's almost inevitable we’re going to have resurgence of the virus," he said. "We’ll have a second wave now if we let all these things go."

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