The paper describes the development and calibration efforts of an integrated freeway and toll plaza model of the New Jersey Turnpike (NJTPK) using paramics microscopic simulation software. The model is calibrated using the detailed E-ZPass data of individual vehicles. The efficiency of the NJTPK is highly related to the toll plaza operations. However, paramics cannot model toll plazas by default. It is also demonstrated in this paper that the application programming interface (API) of paramics is required to model the complex vehicle movements and decisions at toll plazas. The developed simulation model is an invaluable tool in many analyses such as evaluation of traveler information systems, incident management strategies, the effect of infrastructural changes, and the impact of congestion pricing.