Last September, Dallas-area drivers for UberBlack, the company’s high-end car service, received an email informing them that they would be expected to start picking up passengers on UberX, its low-cost option.

The next day, when the policy was scheduled to go into effect, dozens of drivers caravaned to Uber’s office in downtown Dallas and planted themselves outside until company officials met with them. Many had taken out loans to buy luxury vehicles that cost upward of $35,000, and worried that the modest per-mile rate for UberX passengers would barely cover gas and wear and tear, to say nothing of their car payments.

The standoff stretched across nearly three more tense days until Uber allowed them to opt out of the policy. “They thought we were just going to give up, walk away,” said Kirubel Kebede, a leader of the group. “But we said, ‘No, this is our livelihood.’”

In the rapid growth of the online gig economy, many workers have felt squeezed and at times dehumanized by a business structure that promises independence but often leaves them at the mercy of increasingly powerful companies. Some are beginning to band together in search of leverage and to secure what they see as fairer treatment from the platforms that make the work possible.