LOS ANGELES — He knows all about his patients: who likes to cook, whose blood pressure is out of control, who is quarreling with her husband. He keeps track of their appointments and recalls many of their phone numbers by heart. Calvin Woodard isn’t a doctor or a nurse. Woodard is a driver. Every weekday, he ferries dozens of patients in an old white van to and from the To Help Everyone (T.H.E.) Clinic.

As the clinic’s only driver, Woodard, 59, is a critical part of its operations. He is the patients’ unofficial counselor, confidant and, perhaps most important, conscience. He reminds them about scheduled visits, even rousing them out of bed with a friendly phone call. And he urges them to get their tests and vaccinations, even if they are resistant.

Without Woodard, many patients simply wouldn’t show up for appointments. They are chronically ill but live in a world where going to the doctor is not always the top priority. In some ways, the Tennessee native develops a closer relationship with the patients than anyone else at the clinic does. That relationship can translate into results — patients getting the medical care they need.

“He has a rapport sometimes that we can’t have,” said Sharon Leffall, a nurse practitioner and the director of clinical services.

As the federal government invests in community health centers like T.H.E. Clinic and sets high expectations for them to help the nation’s newly insured patients get healthier with less costly care, centers are taking a closer look at some of the barriers facing patients and exploring what can be done to eliminate them.

That’s where Woodard and his white van come in.

Many patients of T.H.E. Clinic don’t have cars — or, if they do, they don’t have enough money to keep them registered or filled with gas. In Los Angeles County, Calif., many clinics are near bus or train stops, but patients often don’t take public transportation and regularly miss medical appointments, sometimes delaying care until they have an emergency. T.H.E. Clinic offers the rides for free.

Nicole Stewart, 29, has Woodard’s cellphone number programmed into speed dial. She said he keeps her on track with her appointments — and he comforts her whenever she is upset.

“He is like a dad I never had,” she said. “I can talk to him.”

Woodard’s daily drives take him on a meandering tour of South Los Angeles, past motels, taquerias, tattoo parlors, check-cashing shops, laundromats and churches. This morning, he picks up Pamela Stamps, one his regulars. “Yes, ma’am,” he says, his way of saying hello.

Stamps, wearing hoop earrings and bright pink lipstick, tells Woodard that she ran out of her blood-pressure medication and has been feeling sick. She missed her last appointment.

“How busy it is today?” she asks him. “I swear I’m not in the mood to wait all day for some pills.”

“That mean you gonna make a scene?” Woodard asks. Stamps tilts her head back and laughs. “Nah.”

Stamps has a car but can’t afford the registration, so she calls Woodard every time she needs a ride. “Calvin is really good people,” she said.