Jhony Barona used to work in fast food and construction. But at his graduation ceremony in August, after training to be a bus driver, he beamed with pride thinking about his new job with Miami-Dade County’s bus system. He graduated with 31 other trainees.

“I feel really, really amazing,” Barona said at the ceremony in downtown Miami. “I’m feeling so good, because every bus operator, every trainee, has a different story. All we have this same dream.”

Transit systems across the United States are struggling to hire and retain bus operators. In Miami-Dade County, that’s led officials to postpone a bus network redesign this year because it will require many new drivers as current operators continue to quit their jobs.

Nearly 20 drivers a month have been leaving their jobs, according to the county transportation department. Some retire, others go to jobs outside or within the county. The county says it needs to hire 200 motivated people like Barona to launch a plan years in the making, called the Better Bus Network, to increase service, add connections and cut wait times.

“Everybody is competing for the same pool of folks,” said Eulois Cleckley, the director and chief executive officer of Miami-Dade’s Department of Transportation and Public Works. “So for us, what we’re saying is that we not only are competitive, we’re best in class.”

The starting salary for new bus drivers is $16.81 an hour. New hires who stay on the job for 18 months get a $5,000 bonus. And benefits include health insurance, tuition reimbursement and vacation time.

Jeffery Mitchell, the president of the Transport Workers Union Local 291, said the bonus is not enough to make up for low pay.

“You’re in a petri dish all day long, stressful condition and this is what they think I’m worth,” he said.

TransitCenter, a foundation that looks at ways to improve public transportation, recently published a report on solutions to the bus operators shortage in the U.S. Its author, Chris Van Eyken, said bus drivers across the country earn low salaries.

“This used to be a good middle-class job and it’s a shame that we would lose this pathway,” Van Eyken said.

Drivers need access to bathrooms, he said, and new hires should get to choose routes and shifts that are often reserved for senior drivers to avoid burnout. And he pointed out attracting drivers means improved transit for customers, too.