FlexRay
A deterministic in-vehicle bus with fixed time slots and two redundant channels, designed for drive-by-wire where CAN fell short.
A consortium including BMW, DaimlerChrysler, Motorola and Philips started work in 2000. Where CAN lets nodes contend for the bus by priority, FlexRay splits every cycle into a static segment with fixed slots per node (TDMA) and a dynamic segment for less urgent traffic. Each channel runs at 10 Mbit/s, and the two channels can carry the same data for redundancy.
The first production use was the 2006 BMW X5, for its adaptive damping. The consortium disbanded in 2009 and the spec became ISO 17458. Mass-market steer-by-wire never arrived, the protocol is laborious to configure, and in newer vehicle architectures CAN FD and automotive Ethernet are taking over its job.