Abstract : Precise timing constraint modeling and analysis is a key point for the correct development of automotive electronics. EAST-ADL and AUTOSAR has been adopted as standards in automotive industry. These standards have recently adopted TADL (Time Augmented Description Language), a timing model for expressing timing constraints. Its current use highlighted different issues, mainly concerning the integration of parameterized multi rate and multi-clock systems. This paper presents new extensions, aligned on AUTOSAR and EAST-ADL, to solve these issues: a support for symbolic timing expression including multi time base description and complex timing constraints. These extensions are applicable at different abstraction levels during design and enable precise modeling of the multi clock characteristics of distributed systems together with parameterized timing expressions. This work has been conducted in the ITEA TIMMO-2-USE project.