“It’s these little glances at the screen that people do in a car,” he said. “We want something that’s very glanceable, that can be seen and done quickly.”

On a recent afternoon, Mr. Brenner drove through the streets here in a Hyundai Sonata equipped with a demonstration version of Android Auto. Part techie, part car guy, Mr. Brenner was hired two years ago after Google discovered he had rigged up a Nexus 7 tablet to his dashboard in an early attempt to make his own connected car.

“Navigate to Krispy Kreme,” he said after settling into the driver’s seat. Up popped the nearest location on the screen, and a voice began turn-by-turn directions. A little music never hurt either: “Play Black Sabbath,” he said.

The Krispy Kreme near Google’s campus played a notable role for Mr. Brenner and his team of engineers. It was the destination they always tried to reach during testing without Android Auto failing along the way.

“They thought we were a little nuts,” he said. “We would pull up with four people taking notes and order three dozen doughnuts for the engineering team.”

It took until last April to finally succeed in making the trip without a glitch. They added some Champagne to bring back from that doughnut run.

When the Android Auto project began, it included a core group of automakers like General Motors, Audi, Honda and Hyundai. Now, as it prepares for its debut, roughly two dozen car brands have signed on to offer it soon. Apple has teamed up with roughly the same number of brands, many of which will offer both systems.