The microsimulation-based Transportation Analysis and Simulation System (TRANSIMS), which represents the next generation of travel forecasting techniques, was designed to model the transportation system of a metropolitan area at an individual traveler’s level. Although the default model parameters in the TRANSIMS traffic signal logic were calibrated to the macroscopic flow relationships contained within the Highway Capacity Manual, to date there has been no research on the traffic signal characteristics of TRANSIMS using empirical data. The TRANSIMS traffic signal logic is examined with an emphasis on how well it could replicate diamond interchange operations. A diamond interchange network was coded into TRANSIMS, and the simulation results were compared with both empirical observations and CORSIM results. It was found that TRANSIMS logic could model the operation of a diamond interchange with respect to offset, cycle length, traffic demand, and signal spacing.