Proposal to modify test procedures for the Alternative Method using heavy-duty chassis dynamometer to determine Usable Battery Energy (UBE) and battery durability requirements for electrified heavy-duty vehicles. Changes include specifications for dynamometer settings, test room conditions, cooling fan requirements, driver breaks, battery preparation and pre-conditioning, soak and charge procedures, discharge test cycles for both plug-in electric vehicles (HD-PEVs) and optimized charge-sustaining hybrid electric vehicles (HD-OVC-HEVs), test termination criteria, and measurement device requirements. The document provides test procedures, tables for driver break allowances based on distance and driving time, and detailed formulas for calculating battery energy changes and break-off criteria.