This paper deals with specific issues related to the design of distributed embedded systems implemented with mixed, eventtriggered and time-triggered task sets, which communicate over bus protocols consisting of both static and dynamic phases. Such systems are emerging as the new standard for automotive applications. We have developed a holistic timing analysis and scheduling approach for this category of systems. We have also identified several new design problems characteristic to such hybrid systems. An example related to bus access optimizationin the context of a mixed static/dynamic bus protocol is presented. Experimental results prove the efficiency of such an optimization approach.