bitbyt3r

One major differentiator for openpilot is the active driver monitoring. If you keep checking your phone while it's activated it will disengage and eventually even refuse to engage. Other systems just make you nudge the wheel, but openpilot uses the front facing camera to watch your eyes.

At least personally (as someone driving openpilot pretty regularly) I'm a lot happier to trust openpilot than the stock system in my car since openpilot watches the driver and nags you (and eventually disengages) if you don't pay attention to the road. With the stock system I have to trust myself more.

Openpilot uses an embedded controller that is connected to the phone via usb to control communication on the CAN busses. It is what enforces the disengagement, and the code on it follows the MISRA standard. The phone can send random commands and you should still be able to maintain control of the vehicle.

The message it's sending is distinct from the torque sensor reading. There is a dedicated message ID for automated steering inputs, usually used for lane keeping assist and for jiggling the wheel as a departure warning.