This paper compares the emerging time-triggered protocols that will find use in automotive control networks. At present there is no de facto standard in the automotive industry for in-vehicle networking based on the time-triggered model. As the industry is pushing towards incorporating X-by-wire technology (X standing for steer, brake, shift, etc.) for future cars, car manufacturers are working towards agreeing industry standards for X-by-wire control system applications. Currently there are four protocols based on the time-triggered paradigm which are competing for the X-by-wire automotive market. These protocols are TTCAN, TTP/C, FlexRay and Byteflight.