“Boredom!” he exclaims on a recent afternoon, when asked why he decided to volunteer for the job.

“Second, to serve the people,” he quickly adds. “Everyone is cooped up at home all day so I may as well do something to contribute to society.”

The job is demanding, Mr. Zhang says. There are typically four drivers assigned to each neighborhood, and many residents have said it is difficult to secure a ride. Some elderly patients have reported walking two hours just to get to the hospital. Mr. Zhang said the number of his rides per day varies.

Driving residents, including the sick, around the city comes with its own risks. Most residents these days are choosing to stay inside as much as possible. An eerie silence has blanketed this once bustling metropolis, punctuated only occasionally by the wail of an ambulance siren or a barking dog.

“Of course, we’re worried about getting infected,” said Mr. Zhang. “Our families are very worried about us, they don’t want us to leave the house.”

Mr. Zhang lives with his parents, wife and two children, ages 3 and 7. The village where he grew up outside of Wuhan recently sent him a notice urging him not to go back, saying he lived too close to the Huanan Seafood Market, where the virus is thought to have originated.