Originally Posted by Bud
"Even hundreds of milliseconds helps," he says. "Because if a car is going to slam on the brakes, it'll slow down dramatically by the time it crashes into you." dopeslap

From this ARTICLE

I thought the idea was that they were safer than a human and wouldn't "crash into you".

Well, really it just means they'll crash into you less often - not never smile

*insert witty remark here*