I was not a grade-school bully, nor was I ever a regular victim of bullying. Like most Americans, though, I definitely experienced isolated bullying incidents—as a victim, as a perpetrator, and as a witness. After watching the first few minutes of the video of school bus monitor Karen Klein being taunted mercilessly by a group of seventh-grade boys, I flashed back to memories of my own school bus days. In my experience at least, bullying and the bus went together like peanut butter and jelly. Fifteen years later, I can still remember the regular cruelty—the times when, for instance, sixth- and seventh-grade boys harassed female classmates sexually.

I also shudder to remember the only time I can recall bullying someone. It was on a school bus during a fifth-grade field trip to the Capitol. My best friend and I were allowed to sit next to each other on the 30-minute drive from Northern Virginia. But a chaperone asked us to accommodate another kid on our seat, a boy with a known mental illness whom I’ll call Jerry. We took out our anger at the three-to-a-seat injustice on Jerry, singing Cypress Hill’s “Insane in the Brain” for what must have been 15 minutes straight as he covered his ears and begged us to stop. It was awful and cruel, but I remember feeling at the time like it was some sort of a game and our victim was somehow in on it, even though many years later I realize he was not. I heard later that Jerry eventually spent time in a psychiatric center because of his illness. This was probably the worst thing we could have taunted him about, and it is one of the most shameful things I’ve done in my life.

When I asked my Slate colleagues for their thoughts, there was general agreement that buses were a rough place. One colleague said the two worst incidents of bullying her child ever faced were both on a school bus. Another said that his mother, a public school teacher, arranged a car pool for him so he would not have to deal with the sort of abuses she knew occurred on school buses.

The research backs up these anecdotes. A 2005 study from the Journal of School Violence reported that two incidents of bullying occurred for every bus ride they monitored. According to a 2007 report by the National Center for Education Statistics, middle school students are most likely to be bullied on a bus. This is also the same age that students are also most likely to be injured by bullying. What is it about buses that make them such an ideal venue for this kind of behavior?

The geography of the school bus certainly plays a big part. When you are on a bus, you are physically trapped. There is nowhere for a victim to hide. Bullies can easily gather around their target in a semi-circle—as seen in the Klein video—or in a seat right next to their prey. As PsychCentral.com Editor-in-Chief John Grohol noted in an article about the Klein case, the constrained environment can lead to a mob mentality. This creates a sense that the individual bullies are an anonymous part of a larger pack, which leads children to lower their inhibitions and behave in ways they normally would not.

The closed environment of the school bus also spurs bullies to ask their victims repeated questions and try to force some kind of response. Without the mob having an opportunity to gather so easily around a trapped person, it’s likely the verbal onslaught of Klein wouldn’t have lasted as long as it did. As is apparent in the video, even a 68-year-old grandmother can feel compelled to respond to abuse in this situation. One kid asks: “Karen, are you sweating? Why is there water on your face?” Klein answers that she is “crying all over.” Another child says, “She probably misses her box of Twinkies.” This taunt leads them all to start asking her, “Do you miss your Twinkies?” They continue to pepper her with questions: “Where do you live, Karen?” “What size bra are you?” “How about I bring my knife out and cut you?” “Why are you looking at me like that, do you want to rape me?” “Karen, how much was that purse?” She answers the question about the purse, and they tell her that it indicates how poor she is. They later mock her for her son’s suicide after she attempts to respond to another taunt.

School buses are also zones of little accountability. Authority figures at school and at home have the power to punish. Drivers and bus monitors, by contrast, have in the past rarely been able to do anything in response to bad behavior. The Klein video seems to demonstrate that there is little a driver or bus monitor can do to stop harassment unless she’s given strong backing from the school system. In a 2010 NEA survey, only 56 percent of bus drivers said they have received training on how to intervene on a child’s behalf when they see he is the victim of bullying. (The Department of Education has thankfully begun working with school transportation providers to disseminate training materials to tens of thousands of bus drivers all over the country.)

One solution that some school districts have adopted is to place cameras on buses, making sure students are aware that they’re being monitored and that their behavior will have consequences. Had the abusers not taped their harassment of Karen Klein, she would probably still be an anonymous education official suffering in silence. In the end, that horrible video could be the spark that’s needed to cut down on bus harassment. Now that there is renewed attention to the problem, hopefully people like Klein and my classmate Jerry will soon be able to ride to school in peace.