Six years ago, less than 4 percent of South Koreans owned a smartphone. Today, that number is 88 percent. That means South Koreans have the highest smartphone ownership rate in the world.

But with great distraction comes great danger. Government surveys have found that millions of South Koreans are "addicted" to smartphone usage, and many more to the Internet in general. According to Korea's Transportation Safety Authority, there were more than 1,000 smartphone-related traffic accidents in 2014, compared with 437 in 2009.

South Koreans have coined terms such as "smartphone zombie" and "human-deer" for the mostly young people who seem to wander obliviously into danger while glued to their screens.

The capital, Seoul, is now trying to stem the tide of collisions, but the plan is decidedly counterintuitive. Starting last week, the city government began putting up signs and placing pavement stickers that would warn smartphone users that they are about to walk into an intersection or otherwise dangerous location. There will be about 300 signs in total.

The paradoxical nature of the plan was clear to most people quoted in a Korea Times article on the signs. A 35-year-old identified by his surname Jun said, "I have noticed the signs on the pavement, but honestly, most people who are peering at their phones on the street aren't going to be able to see them."

Other cities have tried slightly more ingenious methods, such as embedding flashing stop lights on the ground in front of intersections. The Chinese city of Chongqing asked smartphone users to use their own sidewalk lane.

A survey by the University of Washington found that nearly one-third of Americans are busy texting or working on a smartphone at dangerous road crossings. The Department of Transportation has established a clear connection between such habits and an increase in pedestrian deaths.

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