According to Gruber, Field has now joined the "Titan program" dominated by Bob Mansfield. As everyone familiar with Apple knows, Mansfield was Apple's senior vice president of hardware engineering, and retired to take over the company's plan in 2016 from Steve Zadesky.
In addition to Tesla, Field had the experience of serving as chief technology officer at Segway (before joining Apple in 2008) and knew a lot about transportation technology. Before that, Field had worked as a vehicle development engineer and team leader at Ford Motor, and then at DEKA Research.
Apple was rumored to be working on a top-secret plan to build cars in 2014. The plan was supposed to be a full-fledged one, but then the company's executives were replaced and the direction of research and development was adjusted. The Titan project was shelved to focus on unmanned systems (platforms). The latest news about Apple's plans is that the company is working with Volkswagen to refit T6 boxes as an employee ferry, and Apple's test fleet is expanding in California.
Fielder's return has led to speculation that Apple's plans for Titan are "ambitious," and we'll see.