Traffic fatalities increased nationally and in the Washington region last year despite a significant drop in travel because of the coronavirus pandemic.

Excessive speeding was cited as a leading contributor to the carnage. The number of pedestrians and bicyclists killed on the D.C. region’s roadways declined, however, accounting for about one-third of the 258 traffic deaths in the area last year, according to preliminary data compiled by The Washington Post.

Transportation and law enforcement officials say the data confirms that the pandemic, which has killed nearly 500,000 Americans, also altered the dynamics of road safety. Some drivers took open lanes as an invitation for reckless driving, they said, making roadways more lethal in 2020.

Traffic deaths last year were up from 2019, when 249 people were killed in the District and its closer suburbs.

The steady frequency of serious crashes — even after roads emptied at the start of the pandemic — was discouraging for transportation agencies that, in recent years, promised road improvements to reduce highway fatalities and better protect pedestrians and bicyclists who share the road with cars.

The Washington region’s numbers mirror a national trend. Across the country, 38,370 people were killed in highway crashes from January through November 2020, up 7 percent compared with the same period in 2019, according to preliminary federal data analyzed by the National Safety Council. December numbers aren’t yet available.

While Americans drove less because of stay-at-home orders and increased telecommuting, the fatality rate per mile driven rose 24 percent last year, according to the council’s analysis. Meanwhile, the number of miles driven nationwide decreased by 15 percent.

“We should be able to show a significant safety benefit from having less traffic,” the National Safety Council said in a statement last month. “Instead, in the midst of the worst health crisis in more than a century, we are experiencing even deadlier roadways.”

Experts cited speeding and aggressive, distracted and impaired driving as the primary causes for the increase.

In September, a 26-year-old man driving south on Interstate 95 in Fairfax County was killed when a drunk driver traveling “at a high rate of speed” rear-ended his car, police said. Authorities cited speed, alcohol and no use of a seat belt.

Nearly 40 percent of traffic deaths in the Washington region occurred in Maryland’s Prince George’s County, where 99 people died, down one from 2019. Those deaths included 31 pedestrians and one bicyclist, according to data from county and state police.

Neighboring Montgomery County recorded 43 traffic deaths — seven more than in 2019, including one bicyclist and 17 pedestrians.

The District logged 37 traffic deaths in 2020, up from 27 in 2019 and the highest number since 2008, according to city crash data. Twelve of the victims were on foot or two wheels, down from 15 last year in a city that has focused efforts on measures to protect vulnerable road users.

In Virginia, Fairfax County saw a significant drop in crash fatalities: 36, down from 45 in 2019, according to state data. Among them were 15 pedestrians, down from 17 in 2019.

Prince William County had 18 traffic fatalities, up by four from 2019, while five pedestrians were killed. Twelve people were killed in Loudoun County, down from 13 in 2019. In Arlington County, deaths last year fell from six to four — including two pedestrians — and Alexandria’s tally rose to seven, including two pedestrians, from five fatalities in 2019.

Virginia officials say they are troubled by a rise in the number of deadly crashes in which speed was a factor. Speed played a role in nearly half of Northern Virginia’s 79 traffic deaths, according to state records, up from about 40 percent a year earlier.

Virginia State Police Lt. Col. Matthew D. Hanley, director of the Bureau of Field Operations, said a rise in excessive speeding was particularly worrisome on some suburban Washington highways.

“Cars appeared to be racing or traveling at really high speeds on the Beltway, where normally the congestion would prevent folks from going that fast,” he said.

He said more analysis is needed to determine the extent that excessive speeding contributed to the increase in speed-related crashes, but last year’s data shows a troubling trend. Because of protests in Virginia last year, Hanley said, state police pulled law enforcement resources from highway safety initiatives to focus mostly on targeting the most dangerous behaviors.

“Certainly anytime you see almost half of your fatalities’ contributing factor being speed, it is a significant problem,” he said.

Of those killed on D.C.-area streets last year, 82 were pedestrians, three were bicyclists, one was on a scooter, and one was riding a skateboard, according to police records. The victims ranged in age from 1 to 93 years old, were of all races and came from various backgrounds.

Among those killed was Larry Willis, 53, the president of a labor federation representing 33 unions and millions of workers. He was riding his bike Nov. 21 when he was struck by a vehicle near the entrance to Great Falls Park in Montgomery County. Willis’s family said it appeared to be a terrible accident at a blind spot.

In Prince George’s County, a teenager died after being hit by two cars on Aug. 22, along a portion of Indian Head Highway miles from where another pedestrian was killed the same month. That same weekend, a man was killed in Falls Church, and another died when a vehicle ran over him in Northwest D.C.

A rise in speeding and reckless behavior last year alarmed police and road safety groups across the nation, prompting increased patrols on some highways and renewed calls for drivers to slow down.

As traffic volumes fell dramatically during stay-at-home orders in late March and April, average speeds increased significantly above posted limits — more than doubling in some cities, traffic data shows — as roads cleared out. Police agencies from New York to Los Angeles reported more speed-related crashes. State troopers in Maryland, Virginia, California and Minnesota reported writing more speeding tickets.

Some drivers in the Washington region were nabbed at speeds topping 130 mph.

Traffic in the D.C. area dropped to 41 percent of pre-pandemic volumes in April last year. By the end of 2020, it was 25 percent below the normal, according to transportation-data firm Inrix.

“You had the open roads and the lack of enforcement and drivers behaving badly and dangerously,” said Jonathan Adkins, executive director of the Governors Highway Safety Association, a D.C.-based nonprofit that represents highway safety agencies. “We heard it everywhere across the country that many people took to the open roads thinking that they could speed, and speed significantly.”

In Gaithersburg, a horrific two-vehicle crash in September left two people dead and prompted neighbors to call for speed-calming measures. In the Sept. 9 crash, police said, the driver and a passenger of a speeding Toyota Supra were killed, and three people in another vehicle suffered serious injuries when they collided on a busy stretch of Muddy Branch Road.

Evan Glass (D-At Large), a Montgomery County Council member who hosted a summit last month on traffic fatalities, said speed is a problem the region needs to address through street design, more enforcement and education.

“Our society is in a constant rush that we need to get to our destination as fast as we can with little regard to other road users, and that is a societal shift that we need to change,” Glass said. “We need people to be respectful to all users of our streets.”

In recent years, the District and neighboring jurisdictions have boosted enforcement efforts through speed cameras and reducing posted speed limits in some corridors. D.C., Alexandria, and Arlington, Montgomery and Prince George’s counties have adopted Vision Zero, a traffic-safety program that aims to reduce traffic injuries and deaths through strategies focused on enforcement, public education, street engineering and data collection.

Some advocates and officials say the measures are effective despite a consensus that more needs to be done.

“We need to rethink our strategy because it seems to be getting worse every year,” Glass said.

In the District, lawmakers in September approved a package of sweeping road-safety measures to accelerate improvements to bike and pedestrian infrastructure, expand the city’s automated traffic enforcement program and boost traffic safety education. Mayor Muriel E. Bowser (D) last year cut the city’s default speed limit to 20 mph, from 25 mph.

In Maryland, state lawmakers are considering legislation to allow counties to lower the speed limits on state highways. Another proposal would prohibit cars from blocking the box at intersections, which is legal in some parts of the state.

In Virginia, Hanley said a new law banning cellphone use while driving should increase highway safety.

Officials said they hope the dangerous speeding seen during the first several months of the pandemic won’t repeat this year as traffic volumes begin to approach near-normal levels in the region.

“If we can get folks to slow down, put their seat belt on and don’t drive distracted, we can really drive the crash rates and the fatal crash rates way down,” Hanley said.