Questions about the design of electronics for use in an automotive environment. (Questions about the installation and use of automotive electronics are unlikely to be appropriate for this site.)
An application field of electronics that requires high reliability and fail-safe systems. Applications can vary widely in temperature ranges and have a wide voltage range, typically 12 V (or 24 V) while off, and higher when on.
Automotive-grade parts are typically better than consumer and commercial-grade parts, near equal to industrial-grade parts, but not as high quality as military or aerospace-grade parts, though this varies based on manufacturer. Military-grade parts are often mandated by law or government regulation/standards.
Questions about connecting electrical devices to a car, or about car repair, may be better suited to the Motor Vehicle Maintenance & Repair Stack Exchange.