In this work presents the modeling and simulation of a braking energy regeneration system in a hydraulic hybrid vehicle. The vehicle used for testing is a 15000 kg heavy duty truck. The proposed regeneration system configured in parallel was subjected to a standard test speed profile such as the NEDC (New European Driving Cycle) and a real speed profile of a delivery vehicle in Colombian territory that was obtained by satellite tracking in order to compare its performance as an alternative in energy saving. A hydraulic circuit has been designed that considers travel characteristics such as track slope and vehicle speed to control hydraulic device displacement and mode of operation (braking and propulsion), as well as the dynamic model of the vehicle. The simulation has been developed in Matlab Simulink. The results of the model simulation are compared according to the torque required by the vehicle, the regenerated torque and the final torque. System performances are also compared with constant and variable displacement hydraulic device based on speed profiles and show a decrease in the torque spikes required in both the fixed and variable displacement of the hydraulic device, these energy savings have been estimated with the calculation of the power consumed based on time and are reflected as a percentage of the total required power. The development of the simulation yielded savings percentages of 15.5% and 22.5% for fixed and variable displacement respectively.