Early one Saturday morning in April 2016, 41-year-old Scott Franklin got out of his car at a red light and approached another vehicle, one of two filled with young men out partying. Franklin, who was on his way home from working a shift at a Mexican restaurant, was angry: The dispute, police later said, was over whether one car had cut off the other.

As Franklin neared one of the other vehicles, 22-year-old Malcolm DiPina, who was riding in the backseat, drew a .40-caliber Glock pistol, rolled down his window, and fired three to five times. Franklin collapsed in the street, and died soon after. The car sped away.

Everyone gets frustrated while driving, and almost everyone acts out, on occasion. A 2014 study by the AAA Foundation for Traffic Safety found that half of all drivers had purposely tailgated another vehicle, yelled at another driver, or honked a horn “to show annoyance or anger” at least once in the past year.

Sometimes, confrontations escalate, and words, or even bullets, fly. Twelve percent of drivers reported that they had cut someone off on purpose, and nearly 4 percent said they had exited their vehicle to confront another driver. The popular term for the cauldron of feelings that boil over after what often begins as a minor traffic-related dispute is “road rage.”

Law enforcement agencies do not collect data on road rage episodes as a specific category. But an analysis by The Trace of cases logged by the nonprofit Gun Violence Archive indicates that drivers are pulling guns on each other more and more, and that the number of people killed or wounded by a bullet on America’s streets and highways is on the rise.

The Gun Violence Archive uses news and police reports to track incidents of gun violence in the U.S. The organization’s researchers tag each incident with descriptors that seek to describe the factors at play. The Trace’s analysis found that incidents categorized as road rage — broadly, where someone in a car brandished a gun in a threatening manner or fired a gun at another driver or passenger — have more than doubled in the last three years, from 247 in 2014 to 620 in 2016.

All told, there were at least 1,319 road rage episodes involving firearms over that span. Nationwide, at least 354 people were wounded and 136 people were killed.

This total represents just those cases serious enough that police were called, or a news outlet published a story. The motivation for an altercation is not always clear, but most of those counted as road rage by the Gun Violence Archive appear to involve a dispute between strangers. A handful of incidents appear to have been gang related.

The highest-profile recent road rage incidents involved two NFL players, Joe McKnight and Will Smith, killed last year in separate road rage shootings in New Orleans. Victims in 2016 also included a 3-year-old boy, killed when an Arkansas man became enraged at his grandmother for driving too slowly, and shot at the car. In another episode, a soldier who had just returned home to Houston, Texas, was shot in the head and left paralyzed by an angry driver.

There’s no way to say for sure what is responsible for the increase in gun-related road altercations. States with large numbers of concealed-carry permit holders, and relaxed gun laws — like Florida and Texas — experience heightened levels of road rage gun incidents, according to the data. There were also clusters of incidents in cities with high violent crime rates, including Chicago, Memphis, and St. Louis.

More guns in more cars may simply equate to more road rage incidents in which a gun was brandished, or fired, research suggests.

A 2006 study of aggressive drivers by researchers from the Harvard Injury Control Research Center found that drivers with a firearm in their vehicle may be more prone to anger, and more likely to engage in aggressive driving than those who did not have a gun. Across all demographics and regions, gun carriers were more likely to make obscene gestures at other drivers, aggressively follow them, or both, the study concluded.

Mary Vriniotis, a Harvard researcher who worked on the road rage study, said that drivers who feel slighted or endangered may feel they need to react quickly or miss their opportunity, a perspective that can cause a conflict to quickly escalate.

“Most people are not going to take down a license plate and follow them home and find some way to make the point clear later,” Vriniotis said. “I think the question of impulsivity is important to understand better, in terms of gun violence.”

Road Rage and Guns: An Interactive Map (includes all incidents from January 2014 through March 2017)

An invisible presence

The term “road rage” was coined by a local news station in Los Angeles to describe a slew of freeway shootings in 1987. Apparently pushed over the brink by the legendary Los Angeles gridlock, drivers committed almost 70 shootings over 10 weeks, killing five and wounding 11. As road rage became acknowledged as a phenomenon, some drivers reportedly started carrying guns for self-defense purposes.

One of the 1987 cases began when a man named Paul Gary Nussbaum attempted to cut through bumper-to-bumper traffic outside Los Angeles by driving on the right shoulder of the Costa Mesa Freeway. Albert Carroll Morgan, who had just cursed at another driver doing the same thing, shot at Nussbaum as he passed, paralyzing him.

Later reflecting on the moment of fury at his trial, Morgan said he hadn’t considered how dangerous his actions were at the time.

“It’s been a nightmare to me, but it’s been an even greater nightmare for him,” he said.

The media called it a new “epidemic” of driving while angry. Congress even held a hearing in 1997 to discuss possible remedies to the road rage problem, including widening roads and stepping up traffic enforcement.

Yet in all the breathless coverage of road rage that followed these shootings, the role of guns was rarely discussed or studied. Over the next decade, reports zeroed in on the question of why drivers were getting so frustrated, not how they were choosing to express it. Various theories pointed to violent movies, political correctness, high-performance vehicles, and advertising as possible causes of road rage.

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“Why do all the rules of civility fly out the car window on the roadway?” lamented one Los Angeles Times commentator in 1997. “Why must the human animal, once encapsulated in high-speed metal cocoons, be the first, fastest and baddest of the pack?”

Aggression and anger are a key part of human nature. The challenge is how to limit the damage those human emotions can cause, and regulations on gun ownership and carry may be a direct way to do so, experts say.

In a 2015 study, Jeffrey Swanson, a professor of psychiatry and behavioral sciences at Duke University who studies the relationship between anger and guns, discovered that nearly 1 in 10 people display impulsive anger and keep firearms at home, and that 1.5 percent of people display such behavioral traits and carry guns outside the home.

“Everybody should be angry. Everybody does get angry,” Swanson said. “But this is anger that is destructive. It’s unpredictable, it is uncontrolled, it’s impulsive. These are the kind of people who, when they get angry, they break and smash things and get into fights, by their own admission.”

The “Wild West,” in the Sunny Southeast

Florida led the nation in road rage incidents with 147 reported from 2014 to 2016, outpacing states with larger populations, including California and Texas, according to Gun Violence Archive data. Thirty-three people were wounded and 15 were killed in the Florida shootings.

“It’s kind of the Wild West on the road here,” said Thomas Gabor, a criminologist based in in South Florida and author of the book Confronting Gun Violence in America.

Road rage assaults have risen in Florida, from at least 27 cases in 2014 to at least 80 last year.

To try to cut down on aggressive driving and the ensuing body count, the Florida legislature passed a law in 2012 that makes it illegal to drive more than 10 miles below the speed limit in the left lane if another car is coming up from behind. Another law, passed in 2009, requires drivers who have been in three crashes in three years to go back to driver’s education classes.

The state’s law enforcement agencies have also created safety campaigns coaching drivers to be more patient and launched ticketing blitzes targeting aggressive drivers. Lieutenant Greg Bueno of the Florida Highway Patrol said his agency focuses “very heavily on aggressive driving and road rage.”

The Highway Patrol also holds community meetings to educate drivers on road etiquette or how to handle an aggressive driver in a way that doesn’t escalate tense situations.

“We run initiatives throughout the year specifically targeting aggressive drivers to try to hit it at that point before it reaches that level of someone bringing a firearm in,” Bueno said.

In Tampa, a police officer appears on a local morning show once a week to give traffic safety tips.

Road_Rage__Shooting_Incidents_Areas_001 (02)

“We try to keep it in the public eye so people are aware to, you know, take a deep breath before you start cursing or getting aggravated at the person driving next to you, or in front of you,” said Eddie Durkin, a Tampa Police spokesperson.

But Florida lawmakers have enacted laws that critics say are contributing to the road rage shooting trend.

The state was among the first to legalize the concealed carry of firearms by private citizens, and has issued more permits than any other. As of March 31, the state had 1.74 million valid permit holders, an 83 percent increase from 2012 — and almost 500,000 more than Pennsylvania, which had the second-highest number of permits.

In 2008, Florida adopted a law that requires business owners to allow employees to leave firearms in their vehicles on company property.

Florida also is one of more than two dozen states with a “stand your ground” statute, making it easier in many cases for a shooter to mount a successful self-defense claim. DiPina, who shot and killed Franklin in Tampa, was later arrested and charged with manslaughter — but prosecutors eventually dropped the case, having determined that the shooting was justified under “stand your ground.”

The state legislature is currently considering amending “stand your ground” in a way that critics say will give gun-packing citizens even more clearance to shoot at anyone they deem a threat. A road rage dispute is the impetus for the push.

Jared Bretherick was vacationing at Disney World with his family when they were almost side-swiped by a truck driver, Derek Dunning, who then stopped in front of them. Dunning exited his vehicle, but when Bretherick’s father displayed a gun, Dunning retreated. But then the younger Bretherick followed Dunning back to his truck, all the while pointing a gun at him. The police arrested Bretherick for aggravated assault.

He tried to claim “stand your ground” immunity from prosecution, but was denied by the judge because Dunning had already backed off at the sight of the gun. Bretherick appealed the ruling, arguing that he should not have to prove he acted in self-defense before going to trial. But the state Supreme Court ruled in 2015 that the burden to show self-defense is on the defendant.

The bill under consideration by the state legislature would shift the burden of proof to the prosecutor in pretrial hearings, making it up to the state to invalidate a defendant’s self-defense claim in order to convince a judge that the case must go to trial. A Senate committee overwhelmingly approved the bill two days after another road rage shooting in Miami left a 62-year-old man in critical condition.

After prosecutors dropped the case against the man who shot Franklin in Tampa, his father spoke to a local news station.

“It was unbelievable someone could roll down the back window of a car, stick a gun out, and shoot you and not be charged with anything, not even lying during the investigation or leaving the scene of a homicide,” he said.

Corrections: The summary of Jeffrey Swanson’s research initially stated that “nearly 1 in 10 people who self-report patterns of impulsive angry behavior keep firearms at home — and that 1.5 percent of them carry guns outside the home.” In fact, his research found that 1 in 10 adults display angry behavior and have access to guns at home; and that 1.5 percent of such adults carry guns with them.

The number of road rage incidents in Florida between 2014 and 2016 was 147, not 146, as originally stated. The story has been updated to reflect these changes.

[Data analysis and interactive map by Anna Boiko-Weyrauch]