We drink. We doze. We text. In the US, 30,000 people die from automobile accidents every year.(Source) Traffic crashes are the primary cause of death worldwide for people aged 15-24, (Source) and during a crash, 40% of drivers never even hit the brakes. (Source)We’re flawed organisms, barreling around at high speeds in vessels covered in glass, metal, distraction, and death. This is one of Google’s "moonshots" -- to remove human error from a job which, for the past hundred years, has been entirely human.
The car itself will be perfectly safe, but, the human factor, such as pedestrians no paying attention to the car or "standard driven cars" have to be considered. Hence the need of airbags outside the car !