Neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, I'm intrigued that the color is relevant in the car's case - wouldn't it be using some sort of radar to detect and map objects rather than vision? I appreciate I am probably missing something.
The 360 degree sensors on the Tesla are for parking only (Personally when I worked on a self driving car we were going with 360 degree camera and doing path planning based on that, but Tesla has opted not to do that.