SAN FRANCISCO — Apple is rethinking what it plans to do about self-driving cars, just as other big tech companies appear ready to plow ahead with competing efforts.

In a retrenchment of one of its most ambitious initiatives, Apple has shuttered parts of its self-driving car project and laid off dozens of employees, according to three people briefed on the move who were not allowed to speak about it publicly.

The job cuts are the latest sign of trouble with Apple’s car initiative. The company has added resources to the project — code-named Titan — over the last two years, but it has struggled to make progress. And in July, the company brought in Bob Mansfield, a highly regarded Apple veteran, to take over the effort.

Apple is not the only big tech company pursuing autonomous driving technology. Alphabet, the parent company of Google, has tested self-driving cars on the road for years, but its focus has been on designing the underlying software and systems to make that technology work. Tesla has a self-driving feature within its cars that has come under scrutiny in recent months after a fatal accident was connected to its use.