The focus of this paper is the design, implementation, and initial testing of a plug-in hybrid electric vehicle drivetrain in a 2009 GM compact SUV base vehicle by the University of Victoria's EcoCAR Team. The Team is using a condensed three-year vehicle development process modeled after those used by Tier 1 automotive manufactures, and mandated by the competition rules of EcoCAR: The NeXt Challenge.During the first year of the competition, intensive research was performed to identify a powertrain architecture that would give the best overall performance based on greenhouse gas emissions, criteria air contaminant emissions, fuel economy, petroleum use, and vehicle performance according to the weighting formulas of the competition. As a result, an extended range electric vehicle utilizing GM's Two-Mode transmission, a large lithium-ion battery pack, and a rear traction motor was selected; these components were integrated into the vehicle in the second year of the competition. The overall strategy was to achieve a significant all-electric range in all operating conditions, including all segments of the mandated driving profile, to yield maximal emissions-related performance according to the defined utility factor curve, while maintaining full vehicle functionality in all operational modes.This paper will briefly summarize powertrain component selection, and then focus on vehicle control system development and subsequent initial testing and optimization of vehicle systems during year three. The Team is relying heavily on hardware-in-the-loop (HIL) simulations with detailed system models to optimize the vehicle's control strategy. Development and testing of the HIL system and vehicle, including linkages between HIL and real-world testing results, will be discussed. The goal of this work is to smoothly blend power from an internal combustion engine and three electric machines on-board driving all four wheels to maximize propulsive fuel savings and regenerative braking operation.