As Uber prepares for its stock market debut Friday, its long-term success or failure will largely depend on the nearly 4 million drivers who serve as the backbone of the company's network.

The ride-hailing company will need to convince drivers to stick with it as it grapples with complaints over wages and the way it classifies drivers as contractors instead of employees.

Lyft is dealing with similar issues and on Wednesday, drivers for both companies participated in strikes across the country, pledging to turn off their apps for hours to call attention to their plight.

"The drivers are the one who helped Uber to be $100 billion, nobody else, and the drivers are the ones who are suffering," said Inder Parmar, 54, an Uber driver in New York City.

According to the Economic Policy Institute, the average Uber driver earns just above $9 an hour when vehicle ownership and other expenses are factored in.

In a statement, an Uber spokesperson said, "We'll continue working to improve drivers' experience for and with them, every day."

Some drivers, like Ulisis Castillo, are satisfied with the extra income. 

“Right now for me, my wife, my son is 22 years, the money is good for me every week,” he says.

Drivers aren't the only ones who want fair treatment, passengers also putting in their requests: cheaper rates.

Marlene Batkiewicz admits that she doesn't always tip on a more expensive ride, but says workers deserve job security.

“Everybody is just trying to work and get by and live and everything costs more than it used to,” she says.

AP Wire Services contributed to this report.