There are authorities that are relevant for automotive embedded software safety. Groups such as the UK's MIRA have a working group, MISRA (Motor Industry Software Reliability Association) which define a safe subset of C that is workable for embedded systems.
Specifically, undefined, unspecified and implementation-dependent behaviour of the C standard is identified, and the unsafe aspects are prohibited as part of the MISRA-C subset.
Alongside this, embedded system vendors in the automotive industry have serious validation requirements both from clients, and from internal compliance processes - the SEI's CMMI and ISO 26262 are a couple of standards that come to mind.
Keep in mind, this may be a little out of date - it's been a few years since I worked in automotive, but the people working in the industry do take it very, very seriously.