A new approach to handle the inductance effect on multiple signal lines is presented. The worst case switching pattern is first identified. Then a numerical approach is used to model the effective loop inductance (Leff) for multiple lines. Based on look-up table for Leff, an equivalent single line model can be generated to decouple a specific signal line from the others to perform static timing analysis. Compared to the use of full RLC netlist for multiple lines, this approach greatly improves the computation efficiency and maintains accuracy for timing and signal integrity analysis. Applications to repeater insertion in the critical path chains are demonstrated. For a single line, the RLC model minimizes delay with fewer number of repeaters than RC model. However, for multiple lines, we find that same number of repeaters is inserted for optimal delay according to both the RC and RLC multiple line models.