The design of complex distributed embedded systems often presents great challenges because of the large number and dimensions of their components. This research paper discusses some of the problems of designing such systems. The use of Colored Dynamic Activity Diagrams for modeling complex real-time systems is suggested as a possible solution. The Colored Activity Diagrams bridge a gap between modeling technique and description power of High Level Petri nets. By coloring Activity Diagrams the behavior of several objects or processes can be modeled in a single diagram. They also have additional mechanisms for mapping dependences and relationships between individual objects. The color is a property which supports the intended transformation into the High Level Petri Nets allowing further the formal verification of the whole system. The usability of the method is shown in a modeled reference example.