As design complexities increase exponentially, automotive designers need integrated tool environments enabling system-level analyses of alternative architectural solutions. Hence, a huge amount of heterogeneous design data must be made available easily and quickly for the analysis. In this paper, we introduce the AETM (Architecture Exploration Tools and Methods) data model, a key enabler for an integrated model-based tool environment. The data model encompasses several important aspects of the design of any embedded architecture (not only an automotive one), as it supports apture at different levels of abstraction (e.g., functional, logical, and physical) and across application domains.