Methodologies to model the impact of ramp metering queues on diamond interchange operations were developed in this study. The methodologies are part of an overall research effort to address the integrated operations of a diamond interchange and a ramp metering system. The methodologies were implemented in DRIVE, a computer model characterized as a mesoscopic simulation and analytical model. A mesoscopic model has the advantages of both macroscopic and microscopic models with less computing time while still considering stochastic traffic flows. DRIVE can be used to perform system analysis and evaluation of an integrated diamond interchange and ramp metering system over multiple cycles. The component concerning the diamond interchange operations is documented here, with a particular focus on the impact of potential queue spillback to the diamond interchange signals from ramp metering. The study focused on the two common diamond phasing schemes: basic three-phase and Texas Transportation Institute (TTI) four-phase. DRIVE was validated against the VISSIM microscopic traffic simulation model, and general agreement was found in the results between the two models. For oversaturated ramp conditions with queue spillback, both DRIVE and VISSIM indicated that TTI four-phase favors the frontage road approach, whereas the basic three-phase favors the arterial left-turn movement. DRIVE provides a new analysis tool for analyzing diamond interchange operations taking ramp metering into consideration, which would facilitate studies on.