Most of the random reboots I have experienced are caused when carrying my phone in my hand along with my iPad. I finally thought about it and assumed that the magnets in the smart cover where somehow causing the issue. I tested this and confirmed the cause. When the phone is asleep, putting it next to the iPad magnets will cause a reboot. If it's awake the car mode will activate. After reading this thread I have frozen carhome.apk with TB Pro. I will do some testing over the next few days and report back if my issue has been resolved. I also believe WiFi Tether is occasionally causing some of the reboots.