The woman seated next to them on the Metro Blue Line began speaking louder, and her words became more profane. She started cursing at her boyfriend who had his hand under her shirt. Then, when she announced in full voice she would take off her top and flash the train, that was the last straw.

Michael Payan and Nelson Perez exited the light-rail train at the next stop, ran down the platform and hopped back on finding a seat in a different car seconds before the train pulled away.

“That is how loud and obnoxious they were. It was not worth having to put up with that,” said Payan, 55, of Covina.

As frequent bus and train riders, the two friends said they witness bad conduct “every other day” and occasionally some incidents escalate like the one on the Long Beach-bound train.

Mostly, though, train and bus riders encounter more subtle conduct violations, such as blaring music, loud cellphone conversations of a personal nature, seat hogs and other breaches of the code of conduct.

In a battle to attract more customers and keep the ones they have, the Los Angeles County Metropolitan Transportation Authority as well as smaller bus agencies are launching etiquette campaigns they hope will ward off troublemakers through stricter enforcement, as well as through gentle reminders on YouTube and friendly bus and train placards.

The message: Politeness is just as much of a necessity as a paid fare.

Last month, Foothill Transit, the bus agency serving 300 square miles of the San Gabriel and Pomona valleys and downtown Los Angeles, started posting sun-faded bus cards that prohibit “Purse seating” and “rowdiness,” which the agency calls “A Return to Old Time Etiquette.”

While most people associate etiquette with dinner table manners or how to behave at someone’s home, Felicia Friesema, director of marketing and communications for Foothill Transit, said that’s actually a good place to start.

“The common thing with all of those settings, the dinner table, being in someone else’s home is those spaces become communal spaces when other people join them. And the bus is no different,” she said. “It is a mobile village.”

Why are transit agencies in Southern California reminding passengers about the rules of riding? Some say the number of incidents are growing and that can push riders off the train and back into their private cars. Metro CEO Phil Washington said the agency must strive to create a more pleasant rider experience.

Friesema said Foothill’s ridership is aging. More riders are seniors, but the buses also pick up high school and college students. Posting signs now is crucial, as it is back-to-school time. Implicit in the campaign is making seniors and women feel safe, knowing rules will be enforced.

For Metro, the opening of two new train lines, the Gold Line from Pasadena to Azusa, and the Expo Line from Los Angeles to Santa Monica in the past 1 1/2 years has attracted new riders leaving the cocoon of their passenger cars.

With lines opening in the Crenshaw area and Inglewood, LAX and West Los Angeles in the next few years, Metro will need to convince future riders to keep their feet off seats, not take up more than one seat, or block the doors or play loud music, etc.

More importantly, Metro has had complaints from riders feeling unsafe. By enforcing conduct rules, this could ensure a more pleasant ride, or else new riders won’t stay long.

“We are constantly educating customers as to etiquette,” Metro spokesman Dave Sotero said. Metro soon will unleash a two-pronged approach. In October, it’ll use YouTube videos and apply special enforcement surges to certain lines similar to what was done on the Blue Line this spring.

During a five-week enforcement surge from March 20 to April 21 on the Blue Line from downtown L.A. to Long Beach, sheriff’s deputies and Metro security warned 3,280 people, cited 55 and ejected 2,064.

There were 681 incidents of riders taking up excessive space, second only to people eating and drinking, at 745. Other infractions included: sleeping on a bench, 554; playing loud music, 275; offensive behavior, 116 and other, 572.

The upcoming “Metro Manners” campaign will focus on three areas: no seat-hogging, no blocking the aisles and no eating or drinking, Sotero said.

L.A.-based lifestyle and etiquette expert Elaine Swann makes a living telling people how to get along. She speaks at universities and corporations, appearing on numerous TV talks shows, including “The Today Show” and “Access Hollywood.”

“I believe it is a shift in our culture here in L.A. (to trains),” she said during an interview. “When you have this shift, there are guidelines and social norms that folks in L.A. are not used to.”

One of the most common complaints from women train riders is something called manspreading, when men sit on a seat with their knees wide apart, spilling over into the next seat and intimidating a woman looking for a seat.

In the Blue Line operation, Metro did not cite those who took up two or more seats from manspreading or when riders of either gender put a purse or backpack on the adjacent seat. Citations were issued for playing loud music, eating, drinking alcohol and offensive behavior.

Some say men are unaware of their seat-hogging behavior.

“They may not be cognizant of the etiquette involved in sharing your ride on Metro,” Sotero said.

A study by Hunter College of New York City subway riders found 26 percent of the seated male passengers were guilty of manspreading. These included, in order of the most offenses: men ages 30-39 followed by men ages 40-49.

Kelly Williams Brown, author of the book “Gracious” and an expert on modern etiquette, is familiar with train-riding behavior in New York, Portland and Los Angeles and with the practice of manspreading.

“I have definitely seen that,” she said during an interview. “I have heard from various men that there are anatomical reasons.”

Brown added that studies show women take up less space in public places, including mass transit.

The key to changing behaviors on trains and buses is to recognize you are not alone, she said. Sharing a public ride means checking those natural instincts at the turnstile and opening your eyes.

“Public transportation is not a place for comfort. It is not a place to do what comes naturally,” she said. “A big part of etiquette is paying attention to the humanity around you. It comes down to consideration, kindness and respect.”

For example, the woman clipping her toenails on the Portland light-rail should ask herself where does she think those nails go, Brown said.

Politeness and etiquette often go hand-in-hand with safety, she said. She’ll ask a pregnant woman if she wants her seat. But local train riders interviewed said they’d rather be safe than forward.

Debbie Meyers, 59, of Torrance is a small-framed women. She rides several trains and a bus each day to work and back. She regularly sees men taking up two seats. On the Metro Silver Line, she often hears other people’s phone conversations punctuated with foul language.

“Most people, depending on how long the other person is talking on the phone, they will grin and bear it,” Meyers said.

One time she saw a man eating peanuts and throwing the shells on the floor in the train. Did she tell him to stop?

“No, I didn’t,” she said. “He looked a little, um, off. You know. I don’t know if he would go off on me,” she said, saying it was better to switch seats than confront someone breaking the rules.

Payan and Perez said they rarely alert the conductor or bus operator, even if the end result is that they have to stand for 40 minutes because someone’s taking up two seats or feeling uncomfortable overhearing a stranger’s private phone conversation.

Except for one time. Payan remembers a ride on the Foothill Transit Silver Streak, a crowded commuter bus, that stands out as a shining example of virtuous behavior.

“Everyone on the bus moved over to make all the seats available,” Payan recalled. “This was not typical. But for the whole bus to do that, that was nice.”