There was road rage. But the anger is not just limited to the roadway: now there is sidewalk rage. Here is a description of this phenomenon that is being defined and studied by a several academics:

Researchers say the concept of “sidewalk rage” is real. One scientist has even developed a Pedestrian Aggressiveness Syndrome Scale to map out how people express their fury. At its most extreme, sidewalk rage can signal a psychiatric condition known as “intermittent explosive disorder,” researchers say. On Facebook, there’s a group called “I Secretly Want to Punch Slow Walking People in the Back of the Head” that boasts nearly 15,000 members…

Signs of a sidewalk rager include muttering or bumping into others; uncaringly hogging a walking lane; and acting in a hostile manner by staring, giving a “mean face” or approaching others too closely, says Leon James, a psychology professor at the University of Hawaii who studies pedestrian and driver aggression…

How one interprets the situation is key, researchers say. Ragers tend to have a strong sense of how other people should behave. Their code: Slower people keep to the right. Step aside to take a picture. And the left side of an escalator should be, of course, kept free for anyone wanting to walk up…

People slow down when distracted by other activities, too. A 2006 study by the City of New York and the NYC Department of City Planning showed smokers walk 2.3% slower than the average walker’s 4.27 feet per second. Tourists creep along at an 11% more-leisurely rate than the average walker, while cellphone talkers walk 1.6% slower, according to the study. Headphone wearers, by contrast, clipped along at a 9% faster rate than average.

Looking at this from a sociological perspective, sidewalks are problematic because they have a lack of formal rules. They are often wide, particularly in big cities, but there are no markers of where to walk. The situation can become more complicated with dogs, skateboarders, bikers, strollers, tourists, segways, and more. So would the answer to this problem be to institute some guidelines? Why not post signs in public places that escalators should have open lanes on the left?

Yet this lack of rules on the sidewalk can often make them fascinating places to watch or study (if one is not walking at a quick pace through a crowd of people with other objectives). For Jane Jacobs, the sidewalk was where people in the neighborhood gathered to interact and check up on each other. For Mitchell Duneier in Sidewalk, these spaces are where homeless street vendors and others mix, conduct business, and react to differential treatment from the police.

(As a side note, the strategy of the journalist in the second paragraph to cite the size of a relevant Facebook group is a harmful one. This is an interesting article about academic research on a new phenomenon – how does a Facebook group support this exploration? It is simply a number divorced of any context. What if the group had 500 members or if it had 10,000 members? Perhaps it is an attempt to be relevant. But it doesn’t help establish the facts about the phenomenon of sidewalk rage.)