In a statement, Zipcar — a subsidiary of Avis Budget Group, which also owns car rental company Avis Rent a Car — said an outage experienced by a third party telecommunications vendor disrupted connections between the company’s vehicles and its reservation software.

The incident, which lasted several hours and affected an unknown number of vehicles and customers, serves as a reminder of the hazards associated with technology that is increasingly reliant on network connectivity to function.

On Saturday, customers of car-sharing service Zipcar made a startling discovery. No matter what they did or how hard they tried, they couldn’t get the cars they had reserved to turn on.


That meant a number of the company’s more than 12,000 vehicles were reduced to nothing more than placeholders. The doors could open, but the engine and electronic systems wouldn’t respond.

It also meant a number of customers were stranded with cars that didn’t work.

Andrew Jones of Roxbury was stuck on hold with customer service for at least a half-hour while he and his wife waited inside a Zipcar that would not turn back on after they stopped to fill it up with gas.

“We were just waiting and waiting for the call back,” he said.

Customers in other states, including New York, California, and Oregon, reported a similar problem. One user who tweeted about issues with a Zipcar vehicle listed his location as Toronto.

Some, like Jones, stayed with the inoperative cars. Others, including Tina Penman in Portland, Ore., and Heather Reid in Cambridge, abandoned their Zipcar. Penman took an Uber home, while Reid walked from the grocery store back to her apartment.

“I think it has potential to be very dangerous,” Reid said, referring to outages such as the one the company experienced Saturday. “I was lucky I was within walking distance of my home.”


According to Zipcar, less than 10 percent of users were affected, and the issue was resolved the same day. The company did not provide a more specific figure than the percentage, nor did it specify how long the outage lasted or how many vehicles would not turn on.

“We recognize that some members were greatly inconvenienced,” Zipcar said in a statement. “We know that our members rely on our service for a wide variety of trips, and we are continually working to improve our member experience.”

The problem Zipcar users had with their cars on Saturday illustrated the possible hazards associated with technology dependent on Internet connection to function — the so-called “Internet of Things.”

Lou Chitkushev, a professor of computer science at Boston University, said networked technology, such as Zipcar vehicles, will only become more prevalent in the future, as will the problems associated with reliance on that technology.

“We can’t stop the process,” he said. “We are going to have more and more network-connected devices.”

Michael Cusumano, a professor at the MIT Sloan School of Management, said any technological system is bound to fail at some point, and that accepting the risk of that failure is part of modern life.

“I think it’s just one of the trade-offs we accept for the convenience of being able to pick up a car anywhere at any time,” Cusumano said, referring to Zipcar in particular.

Cusumano said even if a piece of technology works 99.99 percent of the time, people will take notice when it doesn’t.


He said the way to mitgate those sorts of issues was by installing redundancies, or backup systems, that can pick up the slack when the primary system has a problem.

Cusumano said Zipcar probably had no such redundancies in place, and recommended a low-tech solution: giving customers the number of a local Avis rental car office who would be able to replace a vehicle that’s not working.

“There’s a kind of primitive, physical solution,” he said. “Sometimes you really need a person to solve this problem.”

Max Reyes can be reached at max.reyes@globe.com. Follow him on Twitter @MaxJReyes.