A lawsuit by Uber drivers seeking to be deemed employees could become a bludgeon against the ride company or end up as a mere mosquito, depending on the outcome of a court hearing in San Francisco.

U.S. District Judge Edward Chen heard arguments Thursday about whether O’Connor et al vs. Uber Technologies deserves status as a class-action case representing 160,000 current and past Uber drivers in California, or whether it should be confined to the three drivers who brought the suit. His decision is not expected for several weeks.

The case’s outcome also looms over other on-demand companies because workers deemed employees have mandates on wages and benefits that contractors do not. It’s the furthest along of a recent raft of worker lawsuits against such firms, and potentially involves the largest numbers of plaintiffs.

Chen appeared skeptical of Uber’s arguments at the hearing’s outset. “Isn’t it contradictory that Uber says every single driver is an independent contractor and yet also says they are dramatically different from one another and thus can’t be certified as a class?” he asked.

Once the suit moves to a jury trial, where it will be decided on its merits, much of the “rights of control” that would be debated are uniform among drivers, Chen said, seeming to indicate that he’s leaning toward certifying the case as a class action. He also indicated that he can see evidence on both sides, pointing out that Uber doesn’t control drivers’ schedules or routes, while it does control fares and monitor their performance using star ratings.

In fact, Uber’s rating system, in which passengers rate drivers with up to five stars, is a major factor. Chen scoffed at Boutrous’ assertion that only some driver contracts specify that they can be “deactivated” for low ratings. “Is Uber going to say that it doesn’t have authority to control someone who … can’t cut it?” he asked.

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Uber submitted as evidence statements from 400 drivers saying they prefer being independent contractors. While that sounds initially impressive, Chen said, measured against the 160,000 potential class members, it’s not even 1 percent. It would carry more weight if those drivers were randomly selected, he added. “I gather that’s not the case,” he said.

Chen also questioned whether the plaintiff drivers had much backing among other drivers. “There’s nothing in the record to show mass support for the position of your three named plaintiffs,” he said to the drivers’ attorney, Shannon Liss-Riordan.

The law is what matters, not drivers’ desires, she said. “This isn’t a popularity contest,” she said. “It’s not a question of what people want.”

She said 1,700 Uber drivers, more than half of them from California, have contacted her firm asking how they can be involved in the case.

Ted Boutrous, Uber’s lead outside counsel, claims that granting drivers employee status would force Uber to clamp down on the freedom they now enjoy, exerting control over when, where and how drivers work. Chen also took issue with that portrayal, saying Uber told the drivers who submitted declarations that they’d lose flexibility if they were employees (though Uber didn’t know if that was true).

“There’s no typical driver at Uber,” Boutrous said at a press event outside the courthouse before the hearing. “No three drivers can represent the hundreds of thousands of drivers in California.”

The stakes for Uber are high. If the drivers win class-action status and ultimately prevail, Uber would be faced with a sweeping overhaul of its relationship with drivers that would “radically change” the app and challenge Uber’s business model, Boutrous said. The company would be on the hook for benefits like workers’ compensation, Social Security payments, guaranteed minimum wage and expense reimbursement.

Uber brought nine drivers to the press event before the hearing to speak about their preference for remaining independent contractors.

“I can log on when I want and Uber has no say over that,” said Sarah Knapp, 58, of Forestville, who’s been driving for Uber since New Year’s Eve. She took off almost two months during a bout of pneumonia without any consequences, she said. “That is the No. 1 thing that draws me to this app, is the freedom of scheduling,” she said.

Aptly enough, Chen’s afternoon docket included a hearing on a recent $228 million settlement by FedEx in the case of some 2,000 delivery drivers who already won a case claiming that they are employees, not independent contractors. That hearing revolved around procedural issues of how the settlement would be parceled out.

While Liss-Riordan cited the FedEx case as a precedent, Uber has sought to distinguish between its drivers and those at FedEx. Chen also weighed in. FedEx had plenty of control over drivers’ hours and routes, he said. “It wasn’t come and go as you please, turn on the app; they had to show up (at certain times) and were shown the routes,” he said.

While Uber’s controls aren’t the same, in some ways they’re even stronger because of the “constant monitoring” of the passenger rating system, Liss-Riordan responded.

In March, Chen ruled that the Uber drivers’ case has enough merit to proceed to a jury trial, as both sides have reasonable arguments. U.S. District Judge Vince Chhabria issued a similar ruling in a case brought by Lyft drivers. Class-action status in the Lyft case will be argued in court in December.

In June, the California labor commissioner’s office found that Uber driver Barbara Berwick was an employee and entitled to reimbursement of $4,152 for expenses.

Uber is appealing that decision, which doesn’t carry the legal weight of a precedent. However, Liss-Riordan referred to it, noting that the decision was based on Uber’s system, not the specifics of Berwick’s situation. “What was material to the outcome was factors that don’t vary,” she said.

Carolyn Said is a San Francisco Chronicle staff writer. E-mail: csaid@sfchronicle.com Twitter: @csaid