The majority of a refuse truck collection cycle consists of frequent Stop and Go events while moving from one household to another. The nature of this driving mission creates the opportunity to reduce fuel consumption by capturing and re-using the kinetic energy normally wasted during braking. This paper includes the evaluation of the brake energy available for regeneration from the conventional drivetrain; the description of the impact of the vehicle variable mass and auxiliary loads; a model validation over a real-world duty cycle; and the potential for an increase in fuel efficiency through hybridization of the drivetrain. The Hydraulic Hybrid (HH) technology is selected since it has a large power density. Special attention is paid to two main issues related to refuse truck modeling: i) the fact that each time the trash bin is picked up, the vehicle mass increases in a discrete manner; ii) the load from the additional auxiliary Power Take-Off unit used to lift and compact the refuse. The model of the complex vehicle system is validated with data from real-world refuse collection duty cycles in Texas.