When the number of coronavirus cases began to skyrocket, several states, including Rhode Island, Florida and Texas, took the unprecedented step of setting up border checkpoints to stop nonresidents who might be carrying the virus.

In Florida and Texas, state troopers are requiring motorists from out of state and their passengers to sign forms promising to self-quarantine for 14 days. Florida, Rhode Island and Texas also require travelers to provide an address where they plan to shelter — and advise them to be prepared for a ­follow-up call or unannounced visit from public health officials.

While the efforts initially targeted residents of New York, which has the most coronavirus cases, they quickly expanded. At local checkpoints for people entering the Florida Keys and North Carolina’s Outer Banks, police ask motorists for ID. Only those with a local address or proof of residency, such as a special resident permit or utility bill, are allowed to proceed.

Law enforcement experts say such broad use of police — and in some cases the National Guard — to set up roadblocks is extraordinary in the United States. Checkpoints are typically reserved for the occasional drunken-driving crackdown or seat-belt check, or the rare search for an escaped prisoner or particularly dangerous criminal.

Singling out motorists with out-of-state license plates as a public health measure is irrational, some legal experts say. Doing so assumes that those drivers and passengers are at higher risk of carrying the virus than residents — even if they’re coming from the same covid-19 hot spot.

It’s also unconstitutional, some legal experts say, to impede citizens’ travel based on their license plate, even if they’re eventually allowed across a border.

The checkpoints typically don’t apply to drivers of commercial, military or emergency vehicles, officials said.

“To stand at the border and refuse entry to another American citizen is something that I would say was unprecedented,” said John DeCarlo, a former police chief in Connecticut and director of the master’s program in criminal justice at the University of New Haven. “Certainly legal scholars will be looking at this [and] asking a lot of questions.”

Protecting local residents

In mid-March, with no cases of the coronavirus reported in the Outer Banks, Dare County closed its borders to outsiders, hoping that residents could ride out the pandemic in the quiet beach towns of North Carolina.

At checkpoints staffed round-the-clock, sheriff’s deputies at the barrier islands’ entry points turn back anyone lacking proof of residency or essential business there. Closing the county’s borders, local officials said, was necessary to prevent a covid-19 outbreak from overwhelming its lone 19-bed hospital.

“We certainly want to keep the virus from spreading, but as important, if we do get it, we want to be sure we can take care of whoever gets sick,” County Manager Robert L. Outten said, noting that the barrier islands share 15 ambulances and that the county’s hospital doesn’t have an intensive care unit. “We can’t do that with hundreds of thousands of people here.”

County officials say the checkpoints have kept the number of people down in a community where the year-round population of 36,000 swells to as many as 300,000 as visitors flock to its 100 miles of shoreline during the summer peak.

But the restrictions have drawn complaints — and at least one lawsuit — from people who say the rules prevent them from reaching their vacation homes, for which they pay property taxes.

Six residents from Maryland, Virginia and South Carolina who say they weren’t allowed to use their second homes in the Outer Banks filed a lawsuit against the county last week alleging that the closed border is unconstitutional because it discriminates against out-of-state citizens.

“Just because you have a state of emergency does not mean that the government can suspend all your constitutional rights,” said Chuck Kitchen, a lawyer in Raleigh, N.C., who is representing the property owners. “You’re seeing that across the country. It’s pretty straightforward. My clients just want to get to the property they own.”

Another property owner, Denny Lawver, said his family would like to socially distance in their condo in Rodanthe while enjoying the Outer Banks’ magnificent sunsets.

“It’s very frustrating to say that even though I pay taxes that I’m not allowed to go there,” Lawver said from his home in Lancaster, Pa. “I’m doing everything that I need to do, and I’d be doing the same thing down there. I respect the guidelines. So what’s the difference if I do that in Pennsylvania or I do it in Rodanthe?”

But Donna Roark, a resident of Kill Devil Hills, said she worries that Outer Banks towns aren’t equipped for a coronavirus outbreak extending beyond year-round residents.

By Easter Sunday, the county had 15 confirmed cases of the virus, including one death.

“We realize that our lifeline is tourism,” Roark said, “but right now protecting our community has to come first.”

Delaware State Police recently set up checkpoints on roads leading to Rehoboth and Bethany Beach. An emergency order by the governor authorizes all police in the state to stop any vehicle “simply because it is displaying an out-of-state tag,” the agency said. The state police also have been seeing and stopping residents from Pennsylvania — which has closed its liquor stores — who are crossing the state line to buy alcohol.

State police in Maryland and Virginia, both states with extensive beaches and stay-at-home orders, said they have no plans for checkpoints. Neither state has quarantine requirements for arriving travelers.

But that doesn’t mean that there haven’t been complaints or that these states are throwing open the door to outsiders.

Ocean City Mayor Rick Meehan said the town has repeatedly asked visitors not to come, and the boardwalk and beaches are open only to year-round residents — practicing social distancing. But Meehan said police aren’t checking the IDs of motorists entering the town. Instead, he said, they’re fanning out across the town as a “very strong police presence” to remind people they see about the need to practice social distancing.

By late March, checkpoints had turned the Florida Keys into a gated community. More than 4,000 cars have been turned around since March 27, when local authorities set up checkpoints on Route 1 and County Route 905 — the only ways into the Keys, according to the Monroe County Sheriff's Office.

“Orders are orders,” said Adam Linhardt, a spokesman for the sheriff’s office, which is restricting access to the Keys to permanent residents.

Anna Kovach, 20, a freshman at the University of South Florida, drove home to Key West just before the checkpoints took effect. Kovach said she agrees with the need to keep out day-trippers and weekend visitors, even those who own second homes in the area, to stop the spread of the virus.

Even so, Kovach said, “I never thought I’d live through something like this. These are things you see in the movies, but I guess we’re living through it.”

Of course, where there’s a roadblock, there’s someone trying to get around it.

Monroe County authorities said that they’ve caught motorists using counterfeit reentry stickers and that they arrested a Wisconsin woman who attempted to drive straight through a checkpoint.

In the Outer Banks, deputies have ticketed four people who tried to get around the checkpoints and turned around about three dozen who tried to cross the Currituck Sound by boat. Officers also found one nonresident who tried to sneak in on a tow truck and another hidden in the trunk of a car.

Constitutional questions

Legal experts say state governments and police have broad power in a public health emergency, including the authority to order a quarantine.But some say that some checkpoints appear to violate constitutional protections of free travel.

Meryl Chertoff, an attorney and law professor leading the Georgetown Project on State and Local Government Policy and Law, said the Constitution prohibits one state from discriminating against residents of another unless there is no less-restrictive means to accomplish a legitimate goal.

“The problem here is that you don’t know who is infected,” Chertoff said. “If we get to the point where there’s rapid testing, then they could set up roadblocks and run a spot-test and turn around people who are sick. But in the absence of that, these roadblocks are way overbroad and are interfering with the right to travel.”

Even some in law enforcement question their effectiveness, saying checkpoints are labor-intensive, inefficient and, amid a deadly pandemic, potentially unsafe for officers. They also can rattle an already anxious public and undo years of efforts to improve police-community relations.

“I think it puts police in a very difficult position,” said Chuck Wexler, executive director of the Police Executive Research Forum. “We espouse community policing and suddenly we’re looking at people because they have a New York license plate.”

Public health officials say the approach could prove useful by discouraging people from traveling unless absolutely necessary or by convincing them to self-quarantine if they do. But the effectiveness of roadblocks is limited, experts say, now that the virus has taken hold in all 50 states.

“If states with police checkpoints think they’re going to stop the disease, that’s not going to work,” said Boris Lushniak, dean of the University of Maryland School of Public Health. “But what may work is if I get pulled over and someone tells me what the rules are” to self-quarantine.

Lushniak said public health officials have long assumed that the federal government would coordinate the response to a national health emergency. Most, he said, hadn’t anticipated that states would institute their own travel restrictions and use roadblocks to enforce them.

As for requiring motorists to provide health information or addresses of where they plan to self-quarantine, Lushniak called such paperwork “a waste of time.” Health departments are probably too swamped with local cases, he said, to ever follow up.

Scott Burris, director of the Center for Public Health Law Research at Temple University’s Beasley School of Law, said states would be better off using variable highway signs, rather than labor-intensive checkpoints, to inform motorists about such orders. Police, he said, should focus instead on patrolling communities to prevent people from congregating and urge them to stay home, regardless of where they come from.

“We’re all exposed now — that’s how we have to think about it,” Burris said. “There’s no geography to this now. It’s a national problem.”

Travel dropping significantly

Up to 16 state troopers guard the borders along Interstates 95 and 10 in Florida.

As of late last week, more than 5,500 traveler forms had been collected from out-of-state residents entering via those highways. Officials said they have seen a decline in the number of people traveling to the state since the policy was implemented March 27.

“It would make it a lot easier if we didn’t have folks coming in from hot zones where they very well may be carrying the virus,” Gov. Ron DeSantis (R) said after ordering the controversial checkpoints along the state’s border with Georgia and Alabama late last month.

Rhode Island was the first state to target motorists with New York license plates; Florida followed — although it had begun asking visiting New Yorkers arriving by plane to self-quarantine much earlier.

Drivers entering Rhode Island from Connecticut on Interstate 95 encountered signs saying: “All New York passenger vehicles must stop at rest area.” Gov. Gina Raimondo (D) later extended the stops to all out-of-state residents after New York Gov. Andrew M. Cuomo (D) called the policy “unconstitutional” and threatened to sue.

“It is consistent with all the guidance we are getting from the federal government and from experts,” Raimondo said at a news conference. “And it is what I know to be necessary to keep Rhode Islanders safe.”

The American Civil Liberties Union of Rhode Island on Thursday served a demand letter to the state warning that the governor’s orders targeting out-of-state residents create “irrational, differential and discriminatory restrictions,” and are in violation of multiple constitutional protections. It demanded that the state immediately clarify and amend its order.

Traffic data shows that interstate travel has dropped significantly in recent weeks, as more states have instituted stay-at-home orders, according to wejo, a British mobility analytics firm that collects data from GPS sensors in some passenger vehicles.

Beginning in early March, traffic from New York, New Jersey and Connecticut heading across the Georgia-Florida border jumped significantly — as much as 57 percent some days compared with the historical average, wejo spokeswoman Blaire Bauman said.

But since mid-March, the number of motorists crossing state lines nationwide has fallen by about half, according to wejo. Traffic headed to Florida from the New York tri-state area has plummeted by 80 percent.

It’s unclear how much, if any, of the decline can be attributed to the checkpoints or simply to people adhering to stay-at-home orders.

Esha Bhandari, an attorney with the ACLU, said the organization is keeping an eye on the checkpoints’ legality.

“We face a public health crisis, and states are taking a lot of different measures that impinge on liberty in different ways,” Bhandari said. “But highway checkpoints are a stop, and they are subject to constitutional limitations.”