The Atmel (and I presume newer Microchip) datasheet says clearly*
Unless specifically provided otherwise, Atmel products are not suitable for, and shall not be used in, automotive applications.
I wonder how they define an application as being automotive, and if anyone has some real experience with them on this matter?
*ok, in tiny print on page 400-odd.
I can speculate the following ends of a continuum:
- Loading Blink in an Uno, powering it off a AA battery pack, and watching the led blink while sitting with the Uno on my lap in the driver's seat of my car is not an automotive application even though it's in the car
- Taking a 70s points-ignition, carburetor-fueled car and sticking electronic sensors in staetgic places like the venturi, the manifold, the fuel line, the accelerator pedal and so on, and having the Arduino decide the choke and throttle butterfly positions to be controlled by servos, certainly would be an automotive application
I wonder if anyone's ever actually asked them (other than the car companies that is, who probably have huge liaison teams of engineers and lawyers dealing with their component suppliers). I also wonder if anyone had an insurance claim kicked out, or was prosecuted after an incident, for using an Arduino in their car, even if their engineering was flawless.