But the strikes were largely muted. At La Guardia Airport in New York on Wednesday morning, cars driving for Uber and Lyft picked up passengers, and one airport worker said the flow of for-hire cars was typical for the time of day. Most drivers interviewed said they were either unaware of the strike or unable to participate because they needed to earn money.

At the heart of the drivers’ frustration is their status as independent contractors, not full-time workers. Ride-hailing companies argue that drivers prefer the flexible schedule of a freelancer. But drivers lack full-time benefits like health care and have said they have little control over their wages because the companies set the fares and take a cut of the fees they earn from rides.

In Melbourne, Australia, about 30 protesters gathered near an Uber facility, holding signs that said, “On-demand workers demand a living wage,” and chanting: “Uber, Uber, you must listen. We will break your algorithm!” Their complaints included falling pay, long hours and a lack of sick leave.

[Get the Bits newsletter for the latest from Silicon Valley and the technology industry.]

The strikes were timed right before Uber’s public offering, with the company set to start trading its shares on the stock market on Friday. Uber is the biggest of a generation of technology start-ups that base their businesses on smartphones and use so-called gig workers. The company is expected to be valued at more than $80 billion in its I.P.O., and its founders and investors are set to reap billions of dollars in wealth.

But that windfall will largely skip the drivers. Although Uber has said it intends to award cash bonuses to more than 1.1 million drivers — with those in the United States having the option to buy the company’s stock in the I.P.O. — drivers have called that a fig leaf. They said the wealth being gained by top executives and private investors had prompted the action on Wednesday.