In today?s UDSM (ultra-deep-sub-micron)-process-technology-based ICs, dynamic delay variations of strongly coupled lines (due to neighboring net switching activity) make static timing analysis problematic. In this paper, new analytical timing models for RLC coupled lines are presented and their accuracy is veri.ed. Coupled interconnect lines are decoupled into an effective single line model by using effective capacitances and effective inductances corresponding to switching activity. Then signal transient waveforms of the effective single line models are determined by exploiting the TWA (Traveling-wave-based Waveform Approximation) technique. This is followed by single line analytical timing model development. It is shown that the models have excellent agreement with SPICE simulations for various circuit performance parameters such as line pitch, line length, driver/receiver size, IMD-thickness, and aspect ratio.