This paper investigates power management strategies for hydraulic hybrid passenger vehicles. Parallel, series, and power-split architectures are modeled and explored in the Matlab environment using variable efficiency hydraulic pump/motor models. Results are presented using a rule-based strategy with ad hoc selection of engine on/off setpoints for the accumulator and transmission gear shifting. The dynamic programming algorithm is then used to determine the optimal trajectories for engine/hydraulics power splitting for each of the architectures over urban and highway drive cycles. Results are then compared to baseline simulation for improvement. Using the given vehicle parameters, the parallel architecture for both the urban and highway drive cycles was shown to be best. By decreasing the volumetric displacement of the hydraulic pump/motors for the power-split configuration, fuel economy can be improved with a corresponding decrease in acceleration.