This paper proposes an enhanced methodology for AEB system development combining road testing, in-door laboratory testing, hardware-in-loop testing and simulations. The application of the modeling part of methodology is demonstrated using an OEM vehicle system. The physical AEB system is subjected to the AEB City and AEB Inter Urban test series as proposed by Euro NCAP. The test series are executed in a laboratory environment. Simulation models are generated and validated against the experimental data from these test series. System sensitivity is evaluated using a parameter variation study and validated simulation models.