Bob Mansfield had stepped back from a day-to-day role at the company a few years ago, after leading the hardware engineering development of products including the MacBook Air laptop computer, the iMac desktop computer, and the iPad tablet. Apple now has Mr. Mansfield running the company’s secret autonomous, electric-vehicle initiative, code-named Project Titan, the people said.

Mansfield is a very smart guy and is well respected inside and outside of Apple.