SAN FRANCISCO — There are plenty of unanswered questions about how self-driving cars would function in the real world, like understanding local driving customs and handing controls back to a human in an emergency.

Now a start-up called Drive.ai, based in Mountain View, Calif., is trying to address how an autonomous car would communicate with other drivers and pedestrians. The company is emphasizing what is known in the artificial intelligence field as “human-machine interaction” as a key to confusing road situations.

How does a robot, for example, tell everyone what it plans to do in intersections when human drivers and people in crosswalks go through an informal ballet to decide who will go first and who will yield?

“Most people’s first interaction with self-driving cars will not be as a rider, but more likely as a pedestrian crossing the street,” said Carol Reiley, the co-founder and president of Drive.ai. “I think it is so important for everyone to trust this type of technology.”