More people are dying from accidents than from stroke, Alzheimer’s, and diabetes.

The number of accidental deaths in the United States has been growing for years, and nobody seems to be paying attention.

According to the Centers for Disease Control and Prevention (CDC), accidents are now the fourth leading cause of death in the United States. As of 2014, that meant 136,053 deaths per year. That number sits far behind the two leading causes of death in the United States: heart disease (614,348 deaths per year) and cancer (591,699 deaths per year).

However, it may surprise many that accidents kill more people annually than numerous other conditions, including stroke, Alzheimer’s, and diabetes.

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That’s precisely what author Steve Casner examined in his new book, “Careful: A User’s Guide to Our Injury-Prone Minds.” Casner works as a research psychologist at NASA, and holds an interdisciplinary PhD in psychology, computer science, and medicine from the University of Pittsburgh.

“We’ve got this problem with injuries. Fatalities are, for the first time in 100 years, starting to creep up,” he told Healthline.

“There is so much discussion of other diseases, and there should be, but here’s one that has just become the fourth leading cause of death in the U.S., and it’s being underdiscussed.”

His book begins as a primer on public safety: the diligent ways laws and technological developments have made people safer and safer. Owing to common sense rules and devices like drunk-driving laws (first enacted in 1939), seat belts, and smoke alarms, the accidental death rate dropped for most the 20th century.

By 1992, the number of accidental deaths in the United States had been halved from 1 in 20, to 1 in 40.

After that, “The fatality rate just sort of stayed where it was for the next eight years,” Casner wrote in his book. “And then it started rising again.”

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The reason for this is multifold: technological, social, and psychological — and all three tend to overlap heavily.

The most apparent technological danger, especially for teenagers and parents of teenagers, are cellphones. According to a study by the National Safety Council, more than a quarter of all car crashes in the United States are attributed to cell phone usage.

Those numbers are also believed to be underreported.

However, as Healthline reported last year, distracted walking is becoming just as prevalent and dangerous.

A common talking point of 2016 was the release of “Pokémon Go,” an augmented reality game that required players to actually get up and walk around outside in order to play.

The game inadvertently led to numerous tragic incidents — like falling off cliffs, and violent altercations after entering private property — due to players intently focusing on their cell phones, rather than the world around them.

“We’re going to have to adopt a whole new attitude towards being careful, and learn something about how we may not be well-adapted to modern living,” said Casner.

“We’re retooling our world so quickly in ways that challenge our everyday intuitions about survival, and cell phones are just the latest example.”

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Casner accepts that cell phone usage is partially to blame, but he doesn’t point his finger at it specifically for the rise in accidental deaths.

Essentially, we have come to the end of the line in which “putting rubber corners on stuff” or implementing new safety precautions is any more effective than thirty years ago.

Take, for example, the Dutch village of Eerbeek that is testing LED traffic signals built right into the pavement so distracted pedestrians staring down at their phones will notice them. Casner called this kind of safety mechanism a “Band-Aid solution.”

Instead, Casner wrote, “The next safety revolution is going to have to happen in our own minds.”

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Going back to the issue of cell phones, and the myriad distractions they have introduced to everyday life, Casner is more concerned with the psychology of distraction, rather than the phone itself.

Multitasking — driving and using a smartphone, for example — is far more taxing on the human brain than we seem to believe, and that makes it incredibly dangerous.

“We really need to think about the human limits of our ability to pay attention,” he said.

The phone is just the current iteration of a larger psychosocial issue.

“In ten years, this big concern over cell phones will be eclipsed by something even bigger,” said Casner.

However, what he hopes is that his work will play some part in making people more aware of these dangers, and to just pay a bit more attention in their daily lives to the things going on around them.

For all the thought that we give to exercise, diet, and heart disease, we need to be more careful with how we conduct our lives in an increasingly distracted world.

“If we keep pushing ahead with medical advancements and we all live to be 150, the sad truth is that we probably won’t, because we may get killed doing something long before that” he said.