Apple has been keeping most of its self-driving car plans and progress under wraps, but every once in a while, we get a small peek at what the tech giant has been doing. It has revealed in a DMV filing, for instance, that one of its autonomous vehicles was recently involved in a crash in the Bay Area -- and it was caused by human error. According to the document, an Apple test vehicle driving in autonomous mode on August 24th (2:58PM) was rear-ended by a 2016 Nissan Leaf. It happened while the test vehicle was waiting for a safe gap to merge onto the notoriously congested Lawrence Expressway. Apple's car was driving at less than 1 mph, while the Nissan Leaf was moving at around 15 mph.