It started, as it often does, over bus fare.

A would-be rider boarded Chris Day's bus last month in Southeast Portland and dropped a few coins, but short of a ticket, into the fare box. After a brief back-and-forth, the man demanded his change back.

Day said he'd have to call a supervisor to open the fare box, which drivers cannot open. But the man became agitated as he radioed dispatch.

"He was really getting worked up," Day said. "Next thing I know, he cold-cocked me in the face."

The attack, which broke Day's cheekbone in four places, is one of at least nine violent attacks on TriMet employees documented this year. At least 17 more have been shoved, grabbed, kissed, threatened or spit upon.

Reported crimes against TriMet employees jumped 46 percent last year, even as overall crime on the system fell. The number of assaults through October has already topped 2015 totals.

Now the transit agency is taking steps to mitigate the violence, including training drivers in de-escalation tactics and testing barriers to physically separate them from attackers. It's also putting more transit cops on buses and working to expand a state law that puts a stiffer sentence on assaults on transit operators.

"It's a very personal issue to us because our employees are being harmed," said Harry Saporta, TriMet's executive director of safety and security. "Nonetheless, it's a national issue. We're all trying to find ways to protect our employees."

The rise in attacks isn't limited to the Portland area; transit agencies across the country have seen similar trajectories. The issue even caught the attention of Congress, which in its last transportation funding package directed the Federal Transit Administration to adopt new rules to protect transit operators.

But no one has figured out why drivers are more vulnerable when ridership is flat.

Portland Police Commander Sara Westbrook, who leads the Transit Police Division, said some of the perpetrators are under the influence of drugs or alcohol, while others show signs of mental illness.

"But I think most of them are people who just don't want to pay and get aggressive," Westbrook said.

Earlier this year, TriMet convened a committee of drivers and others to study the issue and has since launched some initiatives to stem the trend.

Under one pilot program, the agency will spend about $9,000 to equip three buses with sliding glass panels that partially enclose the driver's seat. The barriers are expected to be installed by the end of the year.

TriMet had considered barriers in the past but found that some drivers were uncomfortable being fully enclosed or cut off from riders. The new panels can be left fully or partially open.

It's also increasing police patrols on buses. Two uniformed officers will ride occasionally on lines where operators have expressed particular concerns.

Westbrook, who oversees transit police, said their presence will help to keep potential offenders on their toes, even if officers aren't on board all the time.

"It sends a message to our operators that we value you and it's important that you feel safe," Westbrook said.

The agency also is looking to the Oregon Legislature to expand a law that makes assaulting someone operating a public transit vehicle a felony. The agency wants the enhanced charge to apply to all uniformed transit workers, including drivers who are not behind the wheel, fare checkers and supervisors.

TriMet also is training drivers in de-escalation techniques to help them avoid or defuse a tense encounter. The training started with a small group this year, and has since been expanded to all drivers.

Saporta said drivers are taught to act as "fare informers," not fare enforcers, and not to personalize the interaction. That means changing the language, saying, for example, "Fares are required on TriMet" rather than, "You need to pay your fare."

"We want others to do that kind of work," Saporta said. "We don't want to blame our operators. We just want them to look at a different approach."

But delegating enforcement can have unforeseen consequences, said Day, who returned to work this month and whose attacker now faces an assault charge.

"You just straight-up ignore (rule-breaking), you'll get those who step all over you," he said. "Then you get complaints from the customers who do the right thing. You don't win either way."

And, he said, it shifts the blame for confrontations to the driver.

"We need to steer away from that and say, 'You were assaulted and it's not your fault," he said.

Now, Day is working to form a sort of support structure within TriMet for other victims of assault. The day after he was attacked, he had to fill out reports and forms with no one to guide him through the process.

"It's one thing to have a manager come up and say, 'I'm so sorry for what you went through,'" he said. "To have another victim come up and say, 'Let's go through this together,' I think would help on both sides."

--Interactive map by Lynne Palombo

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus

This post has been updated to reflect that not all attacks occurred while drivers were behind the wheel. It has also been updated to reflect that a TriMet internal committee studying the issue of driver assaults began meeting this year.