Project Titan initiative is Apple in terms of automotive. In other words, Zadesky is the person who is behind the electric car project belongs to Apple.
The reason for leaving Apple called by Zadesky are personal reasons and not related to performance. Zadesky be called a veteran employee of Apple, because it has been 16 years with the company Apple.
Prior to being in charge of electric cars is a member in the team Zadesky iPhone and iPod. When it was not clear when he will formally resign from Apple, his LinkedIn profile currently states that Zadesky still be an employee of Apple. There has been no official comment from Apple about the resignation Zadesky.
About the electric car, Apple had never admitted that they are building an electric-powered cars. However, for some time back, they have recruited many automotive experts from various car manufacturers such as Ford and Mercedes-Benz.
Apple CEO Tim Cook visited the headquarters of BMW in 2014, and a senior Apple executives also visited the BMW plant in Leipzig, Germany to see the production process made electric car BMW, which i3.