Main Street in Hampstead

In the Carroll County town of Hampstead, a man wearing headphones was recently hit by a freight train as he walked along the tracks. (Kenneth K. Lam / Baltimore Sun / January 9, 2014)

Trains have rumbled through the heart of Hampstead for nearly all of the Carroll County town's 125-year history. Horn blasts from passing trains are a part of everyday life in the community.

So are headphones, earbuds and all manner of modern digital devices that are increasingly distracting pedestrians — often with tragic consequences — in small towns and big cities alike.

On Saturday, a CSX train chugging through Hampstead struck Ethan Plympton, a 23-year-old resident who was walking along the tracks. Police say Plympton did not hear the locomotive's repeated horn blasts because he was wearing earbuds with the volume maxed out.

Such an accident may be rare for Hampstead, but experts worry that the proliferating use of headphones is fueling an increase in serious accidents involving pedestrians.

Last May, a 37-year-old Aberdeen man was struck and killed by a CSX train because he was wearing earbuds and didn't hear it approaching. Last week, an 18-year-old was killed by an Amtrak train in California as she stood on the tracks using earbuds to talk on her cellphone.

"It's akin to wearing sunglasses in the dark," said Dr. Richard Lichenstein, director of pediatric emergency medicine research at the University of Maryland Medical Center.

In nationwide research published two years ago, Lichenstein documented a threefold increase in the number of serious injuries to pedestrians wearing headphones between 2004 and 2011. The overwhelming majority of victims were, like Plympton, men under age 30. And more than half of the accidents involved trains, many of which had "sounded some type of warning horn prior to the crash," according to Lichenstein's research.

Injuries are likely to continue to climb as more pedestrians walk while using mobile devices for texting, surfing the Internet, playing games, talking, and listening to music, experts say.

Jack Nasar, an Ohio State University professor, published research last summer showing that more than 1,500 pedestrians were treated in emergency rooms in 2010 for injuries related to using a cellphone while walking, a doubling of such injuries from 2005.

"If the current trends continue, I wouldn't be surprised if the number of injuries to pedestrians caused by cellphones doubles again between 2010 and 2015," Nasar said in a statement accompanying his research.

Young people between 16 and 25 years old were the most frequent victims of such injuries, the study found.

Nasar said in a phone interview that he continues to gather data on how many pedestrians are using cellphones for talking, texting, Web surfing and listening to music.

As "more and more people continue to buy [headphones] and use them," injuries will continue to mount, Nasar said.

Other research shows that younger users of technology are vulnerable. A study released last year by Safe Kids Worldwide examined the habits of nearly 34,000, ages 16 to 19. It found that "one in five high school students and one in eight middle school students were observed crossing the street distracted," according to the report. Students were most often texting or listening on headphones.

Runners, bikers, and skiers who wear headphones also increase their risk of accidents if they cannot hear noises from surrounding environments, Lichenstein said.

While some state and local lawmakers have taken action to ban texting and walking, private industry is also seeing an opportunity, Lichenstein said. Companies have emerged with earbuds that enable listeners to hear noises around them.

One company, EarHero in Boise, Idaho, advertises on its website that its headphones allow users to "listen to your music and stay aware of dangers in your environment."

Matt Murphy, chief executive of EarHero, started the company with his wife two years ago. The audiologists became increasingly aware of the dangers while seeing skiers wearing headphones zip down mountains without any awareness of others. The company's product sits in the ear but is so small that it allows room for other noises, making it popular with individuals who work in law enforcement.

Another company is AfterShokz of East Syracuse, N.Y., which uses "bone conduction" technology to send music through vibrations that are delivered by headphones placed on users' heads, not in their ears.

"Think about your safety. That's been our key message," said Bruce Borenstein, chief executive of AfterShokz. Outdoor sports enthusiasts are becoming increasingly interested in maintaining "situational awareness" while running, cycling and other activities, he added.