The 17 engineers specialize in designing elements present in both traditional and autonomous vehicles, such as braking and suspension systems, said the people, who asked not to be identified because the moves aren’t public. Many of them originally joined Apple from Detroit carmakers and suppliers. A Zoox representative declined to comment. An Apple spokesman declined to comment.

Apple pared back its automotive ambitions last year after rising costs and headcount at Project Titan, as the program is dubbed. Hundreds of engineers were either fired, reassigned or left of their own volition and the project was given a deadline of late 2017 to prove the feasibility of its autonomous driving system and decide on a final direction, people familiar with its workings told Bloomberg News last year.

Chief Executive Officer Tim Cook said in June that Apple is focusing on autonomous driving systems. That technology could then be licensed to carmakers, or Apple’s efforts to make its own car may be resurrected at a later date.

The latest exodus to Zoox suggests Apple is less likely to revive ambitions to make a car itself. The engineers found themselves increasingly sidelined and surplus to requirements at Apple, and were hired by the startup in piecemeal fashion in recent months, the people said.

Zoox is developing its own car for a fleet of autonomous vehicles. The Menlo Park, California-based company made a series of big-name hires in April, appointing Mark Rosekind, the former administrator of the National Highway Traffic Safety Administration as its chief safety innovation officer, and Ferrari NV veteran Corrado Lanzone to lead manufacturing. The startup was valued at more than $1 billion last year. It has raised more than $250 million, according to data compiled by Bloomberg.

Zoox has also snapped up a handful of supply chain specialists from Apple in the past two years.