The target date for Apple's car project has reportedly been pushed back

Apple's building a car in Sunnyvale, California. The main question is when it will see the light of day.

Apple Car enthusiasts will have to wait a little longer than expected, though, because the team working on the car, known as Project Titan, has suffered setbacks.

That's according to a fascinating article by Amir Efrati in The Information about a set of brothers who work at Apple.

The target date for the car has apparently been pushed to 2021, Efrati writes:

"The group has run into challenges, say people briefed about aspects of Titan along with other reports. Its top executive left in January, a sign that things there weren't going well. One person who worked briefly with the Titan team was told during their tenure at Apple that the company had been trying to deliver a vehicle by 2020 but the target slipped to 2021."

The biggest challenge for the car would be the processing and collection of data from a self-driving car's sensors, which can produce two gigabytes of data per mile.

Apple is apparently storing this data on its own servers, which is why employees from Apple's Siri team, which works on similar problems, have been moving to the car project.

Efrati focuses on three brothers who made the switch from Siri to Project Titan known as the "Sumner boys," who all went to the University of North Carolina.

Apparently, these engineers are important enough that Apple has agreed to let some of them work remotely, which is typically reserved for key employees. One of the Sumner brothers wants to move back home to North Carolina because "living in the Bay Area was too expensive."

Apple CEO Tim Cook has addressed the car project only once in public. At Apple's shareholder meeting, he joked that it was "going to be Christmas Eve for a while" when asked about the Apple Car.

The Information's story is a fascinating look at the internal Apple Car operation five years out from Christmas.