Many people sharing their experiences with sexual harassment and assault have recounted incidents that take place on public transit. (Angela Fritz/The Washington Post)

A man pressing his body too close on a crowded train. A stranger sitting across the center aisle of a bus, whispering obscenities. A group of men standing at a bus stop, freely sharing their thoughts about a woman waiting a few feet away.

As women around the United States and across the world share their experiences with sexual harassment and assault as part of the “#MeToo” hashtag campaign, a theme is emerging. Many of these experiences take place on public transit.

In fact, for many, it’s a depressing but foregone conclusion: If you’re a woman who rides public transportation, you’re almost guaranteed to experience the kinds of demeaning or threatening encounters that fit squarely within the bounds of the #MeToo conversation.

The prevalence of these stories does not surprise Anastasia Loukaitou-Sideris, professor of urban planning at the University of California, Los Angeles.

Loukaitou-Sideris has spent time researching how perceptions of crime and harassment affect women’s use of public transportation — and what urban planners and transit agencies can do to help protect people who are fearful because of their previous experiences with violence or harassment on transit.

One thing is clear from her research, she said: Trains and buses are ground zero for the kinds of incidents highlighted by #MeToo.

Why? It’s inherent to the nature of transit. Buses, trains and stations involve public spaces that feel both vast and intimate, where strangers are plentiful, but the usual expectations for personal space can vanish. Transit infrastructure can be desolate — think a dimly lit bus stop on a sparsely populated street — or treacherously crowded. Opportunities are plentiful for would-be harassers and perpetrators of sexual assault.

According to a 2007 survey of New York City subway users, 63 percent of respondents said they had been sexually harassed on the subway, and 51 percent said they were sometimes or frequently threatened with sexual assault or harassment.

Those incidents can have a real impact on public transit ridership, Loukaitou-Sideris said. For people who are “choice” riders and have the means to drive or use taxis instead of public transit, a negative experience with harassment on a train or bus can lead them to make permanent changes in their preferred mode of commuting.

And even for those who are considered “captive” riders — with no flexibility to use alternate modes of transportation — an incident of harassment or assault can have a long-term impact on mobility. Women and men who experience this type of threatening behavior may make changes in their lives to avoid public transit during certain times of day, or to avoid certain lines, routes, stations or stops.

What’s clear from #MeToo is that interactions with fellow riders on public transit often serve as one of women’s (and, sometimes, men’s) initial experiences with sexual harassment or assault.

And that interconnection can have a long-term effect on their comfort with using transit.

“These experiences that happen very early on — because they’re so dramatic and they make you so scared — they have quite a lot of impact. They may taint your use of public transportation and public settings for a very, very long time,” Loukaitou-Sideris said.

Some transit agencies have taken steps to address sexual harassment by launching awareness campaigns aimed at sending the message to riders that groping, intimidation, and lurid or threatening remarks are not tolerated on public transit. Metro debuted its latest anti-harassment awareness campaign last year.

Still, problems continue. According to statistics released last month, there were 61 incidents of harassment reported to Metro in the first half of 2017 — a significant increase from the 37 incidents reported during the same period in 2016. Collective Action for Safe Spaces, a D.C.-based advocacy organization that works to fight harassment, says that this rapid growth is a good thing.

“We view this increase as an indication that people feel more comfortable reporting incidents on D.C.’s public transit system — and that the ad campaign is working,” said Claire Gould, spokeswoman for the organization.

But riders’ willingness to report such incidents doesn’t change the fact that they happen in the first place.

And the incidents are often committed by repeat offenders. A 29-year-old man was arrested by Metro Transit Police last month after authorities say he committed sexual battery and masturbated on a train. The woman who reported the man to police was able to identify him, Metro says, because she had been targeted by the same man on public transit 18 months earlier.

That man, Nathaniel Tyrone Ford of Southeast D.C., had been arrested at least two dozen times before on charges related to indecent exposure, both on and off public transit. But he continued to use the system because Metro officials don’t have the ability to permanently suspend or ban a rider from the entire transit system.

Despite the prevalence of public awareness campaigns, Loukaitou-Sideris said transit agencies and transportation planners don’t take the problem of harassment seriously enough.

After all, she said, it’s not just a “women’s issue.” It’s a civil rights issue, and an issue of equal access to urban mobility and public services. And more can be done to help discourage harassment and assault, and to ensure that riders feel safe, she said.

For example, bus stops should not be placed in desolate areas or on quiet stretches of urban sidewalk; instead, putting a bus stop near a restaurant, grocery store or other gathering place can help people feel that there are others around to keep an eye on then. Improved lighting in train stations can help dissuade people from thinking it’s okay to inappropriately touch or make comments to other riders.

Countdown clocks, she said, serve as a means to help concerned riders avoid situations that they may assess as dicey. Someone waiting for a bus at night can choose to wait inside a nearby shop or office building, only standing at the stop once the bus is a couple minutes away.

The presence of police can also deter men from believing that they have license to touch, grope or make unwanted remarks to women, Loukaitou-Sideris said. And while surveillance cameras help catch people who commit acts of assault or indecent exposure, they rarely make vulnerable train or bus passengers feel safer. There’s little confidence that someone is watching the video closely enough to stop an attack as it’s occurring.

Most of all, Loukaitou-Sideris said, it’s important to create systems where women are encouraged to report harassment or assault that they experience on public transit — and to feel confident that their accounts won’t be belittled or ignored.

Though many riders, particularly women, may think it’s a waste of time to report a relatively minor incident such as a verbal harassment from a fellow rider, Loukaitou-Sideris contends that documenting such episodes is the only way to get transit operators to pay attention to the problem.

She compared the need for increased reporting on transit to the accusations made against Hollywood producer Harvey Weinstein — the same allegations that helped prompt the #MeToo Internet phenomenon.

“There were so many women that had been victimized and they were not saying anything. And then these articles came out, and everybody realized it’s okay to say something,” Loukaitou-Sideris said. “That’s the best reason to be vocal. It prompts other people to share their experiences and be counted. It doesn’t give an excuse to the rest of society to do anything about it.”