DETROIT — The development of self-driving cars in recent years has been primarily a competition between technology companies and automakers working independently of each other.

But that dynamic changed markedly on Tuesday, when Google said it would expand its testing of autonomous vehicles by installing its technology in a fleet of minivans made by Fiat Chrysler.

The deal is the most prominent example yet of a Silicon Valley company collaborating with a traditional automaker on self-driving vehicles. It could also prove to be a breakthrough in the generally wary relationship between technology and auto companies, and prompt more collaborative efforts.

The deal is a major departure for Google, which previously had chosen to work mostly on its own in creating and testing self-driving vehicles.

For Fiat Chrysler, the arrangement allows the company to gain access to Google’s expertise in driverless cars rather than develop its own technology. Analysts said Fiat Chrysler needed a partner to catch up to other car companies that are investing heavily in self-driving vehicles.

“It couldn’t have picked a better one than Google, which is far down the road with self-driving cars,” said Michelle Krebs, an analyst with the firm Autotrader.

No financial terms were disclosed for the deal, which calls for Fiat Chrysler to provide Google with 100 Chrysler Pacifica hybrid minivans built specifically to accommodate self-driving features.

The companies said that Fiat Chrysler would design and engineer the minivans, and that Google would then integrate sensors and computer systems into the vehicles.

The arrangement is the first time Google has worked directly with an automaker to adapt mass-market vehicles for self-driving purposes. Until now, Google had used an automotive supplier to build its own autonomous-vehicle prototypes.

John Krafcik, the chief executive of the Google Self-Driving Car Project, said the deal was a critical step in efforts to create autonomous vehicles for everyday driving. He said the collaboration “will accelerate our efforts to develop a fully self-driving car that will make our roads safer and bring everyday destinations within reach for those who cannot drive.”

Sergio Marchionne, Fiat Chrysler’s chief executive, has been outspoken in recent months about his company’s desire to form technology partnerships, partly to defray the cost of developing high-tech systems on its own.

“The experiences both companies gain will be fundamental to delivering automotive technology solutions that ultimately have far-reaching commercial benefits,” he said.

Other automakers, such as General Motors and Ford Motor, are also moving rapidly to develop self-driving cars. GM, for example, has agreed to buy the technology company Cruise Automation to begin outfitting its cars with self-driving systems.

At the same time, federal regulators are working on setting new guidelines for self-driving vehicles. Google is part of a coalition — which includes Ford and Volvo — that supports swift passage of rules to allow for driverless cars on the nation’s roadways.

Google is testing its own self-driving prototypes in California and elsewhere. The company has also modified sport utility vehicles produced by Toyota to accommodate self-driving systems.

But the Pacifica hybrid minivan is a larger vehicle that can accommodate more passengers. With features like electronically controlled sliding doors, the van could be well suited to ferrying larger groups of people without the need for an actual driver.

There was no indication that Fiat Chrysler had an inside track to mass produce self-driving vehicles for Google one day. For now, the collaboration is said to be strictly for testing purposes.

The companies said their engineering teams would work together at an unnamed location in Michigan.

“It is a deal that should benefit both parties,” said Jack Nerad, an analyst with the auto-research firm Kelley Blue Book.

Nerad said adapting a gasoline-electric hybrid vehicle like the Pacifica was a logical extension of Google’s testing efforts. For Fiat Chrysler, the deal highlights the attributes of the new version of its bellwether minivan, which is going on sale this year.

“It’s hard to look at this as anything but a win-win,” he said.

The nation’s top auto-safety regulator, Mark Rosekind, said last week that self-driving technology had the potential to reduce traffic fatalities — currently 33,000 a year — on American roads.

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The technology has also been supported by those who advocate self-driving vehicles for disabled people who cannot operate a car, as well as by groups like Mothers Against Drunk Driving that aim to reduce accidents involving alcohol consumption.

Opponents of fully autonomous vehicles have said the safety of driverless cars has yet to be proved, and they cite wrecks involving Google prototypes on public streets.

Currently, there are no federal rules that expressly prohibit autonomous vehicles. But California has proposed that self-driving cars require an actual driver behind the wheel to take control if autonomous systems fail to operate safely.