[Photo by Wang Xiaoying/China Daily]

Forget the undead, it's the mobile device addicts filling the sidewalks that I worry about

Slowly they edge forward, their eyes fixed downward. Their peripheral vision is all but gone, a memory of the life they had before. Now, they merely run on instinct, fueled by a raw desire for braaaaaaaaaains ... well, brain-training apps.

As opposed to the dreaded flesh-eaters in The Walking Dead, the popular comic book and TV show, the "zombies" I encounter everyday on the streets of China are more annoying than scary, and are really only a danger to themselves - unless you count the repetitive strain injury that other pedestrians risk developing from all the tutting and glaring.

I'm talking about smartphone zombies, people who walk while staring at a mobile device, or in other words, the people who have made getting to a subway station in rush hour one big game of human pinball.

I've seen people walking along engrossed in movies or TV dramas on their smartphone or tablet PC who are relying solely on their subconscious memory to navigate busy, narrow and often uneven sidewalks. With earphones applied, they are completely oblivious to the outside world.

Even strong shoulder-to-shoulder contact cannot shake their focus, and if it does their response is usually only a brief look around them, as if waking from a long coma, before their eyes eventually are drawn back to that small screen.

While they may be irritating, observant pedestrians can actually easily avoid smartphone zombies. The real danger is when they come up against fast-moving traffic.

So far, there is little to no data in China on how many people are being injured, or even killed, because of their less-than-smart behavior in the age of smart technology. What evidence is available is mostly anecdotal.

And it's not just China, of course. In the United States, health and safety agencies have roundly warned against people walking while watching their phones.