In the past couple of decades, hospital emergency rooms have seen a dramatic rise in the number of injuries caused by “distracted walking.” Pedestrians with their eyes fixed on the screens of their smart phones or tablets are falling down stairs, tripping over curbs, and stepping into the path of oncoming traffic. These mishaps have become frequent enough that the National Safety Council now includes a “distracted walking” category in its annual injury report. And sometimes more than injury results: the percentage of people killed in distracted walking accidents, while still relatively small, has been…