At least 15 people were killed and 30 wounded in New Orleans early on New Year’s Day, when a man deliberately plowed a pickup truck into crowds on Bourbon Street, local officials said. Authorities are investigating the attack as an act of terrorism.

The incident was the latest in a long string of vehicle-based attacks against crowds, dating back decades. Vehicle ramming did not start as a terrorist tactic, but it frequently has been used by extremist organizations and radicalized individuals to kill, wound and instill fear.

Cars and trucks are ubiquitous, especially in the developed world, and can be repurposed easily into deadly weapons.

Assailants with “limited access to explosives or weapons” can use vehicles to cause great harm “with minimal prior training or experience,” according to an FBI handout on “Terrorist Use of Vehicle Ramming Tactics.”

Vehicle ramming attacks transform “a bland, everyday object into a lethal, semi-strategic weapon,” researchers Vincent Miller and Keith Hayward wrote in a 2019 study published in The British Journal of Criminology. The tactic gives “marginal actors” the ability to “strike at the heart of urban centers and sow fear in the wider society,” they added.

After potential targets such as airports and public buildings became more heavily secured, especially after the Sept. 11, 2001, attacks, some terrorists and other assailants began to use vehicles against more vulnerable targets, such as groups of people congregating in public spaces.

Using vehicles to indiscriminately attack people has a long history, mostly unrelated to organized terrorism, such as the 22-year-old Czechoslovak woman who killed eight people in 1973, citing her grievances against society.

Terrorist groups began using ramming attacks in the 1990s, according to a study by the Mineta Transportation Institute, part of San Jose State University. The majority of the 184 vehicle-ramming attacks from 1963 to mid-2019, when the study was published, took place in Israel and the West Bank.

• Islamic groups: In a 2010 article in its magazine, Inspire, al-Qaeda encouraged adherents to use vehicles “to mow down the enemies of Allah.” But the tactic did not really catch on among would-be terrorists until several years later, when the Islamic State began to call publicly for vehicle attacks.

• New York City: A man drove a pickup truck into a crowded bike path in 2017 along the Hudson River in Manhattan, killing eight and wounding at least 11 before he was shot by police. Notes found near the scene indicated the killer’s allegiance to the Islamic State, authorities said.

• Israel and the West Bank: The use of vehicles as weapons has become common, with dozens of attacks by Palestinians against Israeli soldiers and civilians in the past few decades. The tactic became more prominent in the 2010s, during a wave of “lone wolf” attacks by Palestinians who were largely unaffiliated with organized armed groups.

• Nice, France: More than 80 people were killed and hundreds wounded when a man drove a 19-ton truck through a crowd of spectators watching Bastille Day fireworks in southern France. The Islamic State claimed responsibility for the attack; investigators said the driver had been self-radicalized by watching jihadi videos, with no evidence linking him directly to the terrorist group.

• Charlottesville, Va.: A man drove his car into a crowd of people protesting a gathering of white supremacists, killing one woman and wounding nearly 40. He was convicted of first-degree murder.

• George Floyd protests: During civil rights demonstrations after Floyd was killed by Minneapolis police in 2020, there were at least 66 vehicle attacks on protesters, according to Ari E. Weil, the deputy research director at the Chicago Project on Security and Threats of the University of Chicago. It was sometimes difficult to assess whether the attacks were spontaneous or premeditated.

• China: In November, 35 people were killed after a man drove a vehicle into a crowd at a sports center in the southern city of Zhuhai. A week later, another man drove a car into a group of people near an elementary school in the central city of Changde, wounding students.

• Germany’s Christmas markets: In 2016, a man killed 12 people by driving a truck into a crowd in central Berlin. In December, a man drove into a crowd in the eastern city of Magdeburg, killing at least five people, including a 9-year-old child.

As vehicle-based attacks have become more common, police and security forces have tried to make public spaces a tougher target, erecting barriers such as bollards — short, sturdy posts that are designed to stop a car or truck before it can reach a crowd or a building.