TAMPA — Test change. A fatal knife attack earlier this month has raised questions about what more should be done to ensure the safety of bus drivers. The answer, experts say, may be a mix of technology, training and public awareness. Thomas Dunn, 46, died May 18 when a passenger slit his throat while he was driving a Hillsborough Area Regional Transit authority bus along Nebraska Avenue. Witnesses said no physical altercation preceded the attack and a police investigation found "no evident provocation." In the past 10 years, since 2008, nearly 2,000 bus drivers nationwide have been transported to a hospital with injuries from an assault, according to the National Transit Database. Among the attacks: • Just three days before the Tampa slaying, a Milwaukee woman climbed over a driver's security divider and stabbed him in the arm after he asked her to pay a $2.25 fare, authorities said. • In 2017, a man in Winnipeg, Manitoba, stabbed a driver to death after refusing to get off the bus once it reached its last stop. • In 2012, a passenger shot and killed a bus driver in West Hollywood, Calif. READ MORE: Slain HART driver chose busy route because he ‘loved people,’ friend says An attack that results in death or serious injury is rare, but drivers in Hillsborough know what it’s like to be spit on, harassed and pushed, said Colin Mulloy, safety director with the Hillsbrough authority. "Bus operators are the most front-line employees in a transit agency," said Polly Hanson with the Washington, D.C.-based American Public Transportation Association. "They're trying to provide instructions, give directions and collect fares, all in an unpredictable environment." The Hillsborough authority recorded an average of 13 verbal confrontations a month in the first four months of this year, with just under two per month escalating to physical violence, Mulloy said. In the past four years, 20 Pinellas bus drivers have reported altercations with passengers, according to Pinellas Suncoast Transit Authority data. Two drivers were injured, six were spit on and one had a drink thrown on her. The Pinellas authority saw the number of altercations increase in 2017 and 2018, with nearly all involving arguments that escalated and often arising over fare payment, spokeswoman Whitney Fox said. The agency rolled out new training for drivers that emphasizes de-escalation techniques. No altercations have been reported yet this year. "Hopefully, these efforts are at least partially the reason 2019 has started off so well," Fox said. Hillsborough also offers de-escalation training for its drivers as part of the mandatory safety meetings that drivers attend quarterly, Mulloy said. With 35,000 people riding Hillsborough buses each day, the agency knows it can’t control every interaction, Mulloy said. But training can help keep the lid on. "That's 35,000 personalities with 35,000 good days and bad days,” he said. READ MORE: Assailant in bus attack told driver, ‘God bless you,’ before slitting his throat, report says Because of Dunn's death, the Hillsborough authority will undergo a comprehensive safety assessment and is planning a statewide symposium in July on safety concerns. "There are a lot of different tools out there,” Mulloy said. “We want to find real solutions that work in the state of Florida." Hanson, with the American Public Transportation Association, said transit experts recommend a layering approach. For some agencies, that includes armed guards patrolling stops and riding busy routes. Others, like Washington D.C., run ad campaigns that help passengers and the public connect with the drivers. New technology allows for live video and audio feeds along with panic buttons and emergency messages digitally displayed across the bus. Hillsborough’s was the first agency in the state to install security monitors on its buses, similar to those at drug stores or gas stations, Mulloy said. The agency is still adding the monitors to each of its 180 buses. There was no monitor on the bus Thomas Dunn was driving, along the Nebraska-Fletcher avenues MetroRapid route. Another safety option is a partition separating the driver's seat from the rest of the bus, particularly passengers getting on and off, said Curtis Howard, president of Amalgamated Transit Union Local 1593 in Tampa. The divider, sometimes called a shield, gets mixed reviews from operators, Hanson said. "It has to be the right design, because there's some concern about operators getting out of there quick enough," Howard said. "We have not taken a position with HART on which design, but they know we're very supportive of those." Last week, Hillsborough borrowed a Pinellas bus outfitted with a clear driver-protection partition and invited drivers to check it out. The partition features a swinging, locking door, and the top of the door slides open for easy access, said Hillsborough driver Tisha Jones. The design offered protection but wasn't too confining, said Hillsborough driver Tisha Jones, Local 1593’s legislative coordinator. She said she was encouraged by the Hillsborough authority’s demonstration. "It made me think they care about driver safety," she said. Still, questions arose after Dunn’s death over a complaint he made to the authority board Dec. 3 about driver safety. He described how one passenger spit in his face and tried to break his arm after he asked to see her identification. Dunn spoke to a nearby Tampa police officer but said he got no help. HART pays the Tampa Police Department $120,000 a year to place an officer at the downtown Marion Transit Center, according to payment records. That contract has been in place since 1987, police spokesman Steve Hegarty said. The agency also has contracts for 12 armed guards to patrol around the clock at its operations center at 4305 E 21st Ave. plus three transit stations — Marion, the University Area and Netpark. Five armed guards also patrol the TECO Line Streetcar and the corridor between Marion and University Area transit centers. This all costs nearly $64,000 a month, $765,000 a year. One more safety measure pushed by transit authorities nationwide is holding offenders accountable through the legal system, Hanson said. "They're trying to get prosecutors to take this seriously,” she said, “and make sure that people, when they are apprehended, are prosecuted.” Times staff writer Tony Marrero contributed to this report. Contact Caitlin Johnston at firstname.lastname@example.org or (727) 893-8779. Follow @cljohnst.