Three months after roads emptied amid the coronavirus outbreak, U.S. traffic has rebounded to about 90 percent of pre-pandemic levels as states lift more restrictions, “quarantine fatigue” continues to take a toll and summer weather draws people out, according to travel analysts.

In 22 states, people have begun to drive even more than they did in late February, before government stay-at-home orders began to take effect, according to INRIX, a traffic analytics firm based in Kirkland, Wash.

Those include states with recent increases in coronavirus infections, such as South Dakota at 121 percent of pre-pandemic travel levels, South Carolina at 108 percent and Oklahoma at 105 percent, according to the INRIX data analyzed up to June 12.

Bob Pishue, an INRIX transportation analyst, said the number of miles traveled by passenger vehicles nationwide during the week of June 6-12 averaged 93 percent of miles traveled during the last week of February. He said vehicle mileage has increased steadily since April 9, when average traffic nationwide bottomed out at 52 percent of normal.

However, Pishue said, when seasonal travel changes are factored in, the national average comes closer to 80 percent of what is typical for this time of year. That is because people drive about 15 to 20 percent more in the summer compared with winter months.

“We’re still down,” Pishue said. “We’re just now hitting that February level.”

Many major metropolitan areas also have seen less traffic growth, Pishue said, probably because many people still working from home are not commuting into downtowns and other job centers.

In the Washington region, traffic on June 12 was about 79 percent of late-February levels based on miles traveled, he said. The New York City region was at 82 percent, while Los Angeles hit 85 percent.

Pishue said he was surprised to see that congestion has started to return to some major metropolitan areas, including parts of New York and Los Angeles, perhaps as some people avoid public transportation or as even lower than usual traffic volumes outstrip road capacity. INRIX collects data anonymously via GPS probes on roadways, vehicle navigation systems and other devices.

Smartphone location data being tracked anonymously by University of Maryland researchers shows that miles traveled per person are back to 90 percent nationwide, compared with early March. Unlike the INRIX data, which focuses on passenger vehicles, the University of Maryland’s smartphone data includes travel by all modes, including by car, plane, walking, bicycle and public transportation. Researchers consider the amount of travel to be one indicator of how much an area’s population is social distancing.

Sepehr Ghader, assistant director of the university’s Maryland Transportation Institute, said travel dropped nationwide starting March 15 and began ticking up again in early April. He said he was surprised travel had rebounded so quickly in many parts of the country.

Ghader attributed some of the increase to the typical summer jump as people head out more to restaurants, parks and other leisure destinations. His other theory: People tired of staying home this spring have viewed the lifting of government orders on businesses as a sign that they can resume their pre-pandemic travel habits.

“If people don’t get true guidelines of why they need to behave differently, I think people naturally do what they were doing before,” Ghader said.

The smartphone data also shows the Washington area’s travel lagging more, as the region has reopened slower than other parts of the country due to its higher numbers of coronavirus cases.

As of June 12, the District had hit 74 percent of its pre-pandemic number of miles traveled per person daily. Prince George’s County was at 85 percent, Fairfax County at 74 percent, Montgomery County at 67 percent and Arlington County at 52 percent.

Taran Hutchinson, spokesman for the Metropolitan Area Transportation Operations Coordination program, said the region’s transportation agencies have seen a “slow, upward trend” as local governments have begun to lift restrictions. One sign of increasing traffic volumes: more multivehicle collisions.

“We’re still not seeing the congestion that we’re used to seeing pre-covid,” Hutchinson said, “but you can definitely tell there are a lot more folks out there.”

Even so, he added, highways and major roads remain mostly free-flowing, except in cases of collisions, lane closings and other incidents.

“It’s not anywhere close to pre-covid,” Hutchinson said.

In Northern Virginia, highway officials say they have seen the most traffic growth on Interstate 95 and the least on Interstate 66 inside the Capital Beltway. The Virginia Department of Transportation also began to see traffic congestion on both highways, and on some major arterial roads, last weekend, VDOT spokeswoman Jennifer McCord said.

Travel times are increasing along with traffic. For example, a morning trip on northbound Interstate 395 that averaged nine minutes earlier this month jumped to an average of 23 minutes by June 14, according to INRIX data provided to VDOT. An evening trip on the Beltway’s outer loop between the American Legion Bridge and I-95 has more than doubled since June 8, to 28 minutes from an average of 13 minutes.

The increase in travel comes as Americans tell pollsters they plan to travel less for vacation this summer because of the pandemic. In a Monmouth University poll released June 15, 26 percent of Americans say they definitely or probably plan to travel this summer for vacation, down from 63 percent before the outbreak.

Washington Post polling analyst Emily Guskin contributed to this report.