A greater Portland Metro bus emerges from the wash at the depot on Valley Street in Portland on March 17. Credit: Troy R. Bennett / BDN

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Travel in Maine immediately plummeted after the state announced its first case of the new coronavirus, suggesting people are heeding advice from health officials on social distancing, though it is unclear exactly how it has reduced the spread of the virus.

As of Wednesday, there were 142 confirmed cases of coronavirus in Maine, spanning 10 of the state’s 16 counties. Nirav Shah, the director of the Maine Center for Disease Control and Prevention said that everyone should live as if the virus is in their communities.

On Tuesday, Gov. Janet Mills ordered certain nonessential businesses to close, stopping short of more drastic actions taken largely in more populated and heavy-hit states. She has also ordered restaurants and bars to close to dine-in customers and banned social gatherings of 10 or more people while recommending Mainers stay home as much as possible.

It’s hard to tell exactly how these moves have reduced social contact, though travel and cellphone data give us insight. While it cannot say if Mainers are keeping 6 feet away from one another per federal health guidelines, it suggests people are staying home much more.

Travel plummeted after Maine announced its first case of the virus two weeks ago, with the greatest drops coming in Lincoln, Oxford and Piscataquis counties. Using cellphone location data, the company Unacast found that Mainers had reduced overall travel by about 34 percent between Feb. 28 and March 21. That was behind the U.S. average of 40 percent over that time period, though Maine’s sparse population could explain part of the discrepancy.

Nearly all of that change occurred after the first case of coronavirus was confirmed in the state on March 12, indicating that Mainers took the virus more seriously then. Lincoln County had the largest decrease among counties at 45 percent, with Oxford and Piscataquis counties just behind.

It’s not clear why travel slowed more in some counties than others. Travel is based on a number of factors, including what proportion of the population can work from home and how close people live to essential services such as grocery stores. Those are far away from many in Aroostook County, which saw the second-smallest drop at 22 percent.

State data from more urban areas back this finding up. Overall traffic on the Maine Turnpike, which runs from Kittery to Augusta, recently decreased by about 50 percent, with the most dramatic declines coming in towns around Portland, according to turnpike authority data. Peter Mills, the turnpike’s executive director and the governor’s brother, said that decline had largely been in personal vehicles, while delivery trucks were less affected.

It’s unclear exactly how this is affecting the transmission of the virus, though social distancing is a crucial part of slowing its spread. The Maine CDC has emphasized social distancing measures in order to “flatten the curve” — or slow the rate of transmission of the disease to prevent hospitals from becoming overwhelmed. Reductions in travel are only one indicator of the ways in which Mainers might be avoiding physical contact.

Janet Mills’ response to the virus has been largely incremental. The governor recommended the closure of nonessential businesses before mandating it while saying she wanted to frame the state’s response as outlining what people can do and not what they cannot.

Shah, the Maine CDC director, has cautioned that, while the agency looks at the rate of new cases as an indicator of how the coronavirus might be spreading, it is difficult to evaluate how much social distancing Mainers are doing, or see the effects of it in real time.

The issue of whether the state has done enough, or should have taken harsher steps to reduce social contact, will not be clear until after the fact, though distancing is a proven method of slowing the virus’ spread.

“Based on where we are in our uptick of cases, it is still too early to know,” Shah told reporters Wednesday.