This work supported the Federal Highway Administration (FHWA) in presenting state and metropolitan area vehicle occupancy information in compliance with Title 23 of the US Code of Federal Regulations, Part 490 National Performance Measures. The basic goal is to provide and introduce a statistically effective and realistic approach to approximate bus occupancy rates for each US state and Washington, DC. Bus occupancies were calculated separately for transit buses, school buses, and motorcoaches. The average total bus occupancy was determined by aggregating the average occupancy of the vehicle for the three groups weighted by annual vehicle miles traveled. Regarding transit buses, the National Transit Database (NTD) of the Federal Transit Administration (FTA) was used to measure the occupancy of transit buses. For school buses, state transportation statistics from 2015–2016 were used to measure average school bus occupancy for each state. Data provided by the Port Authority of New York and New Jersey (PANYNJ) for the Port Authority Bus Terminal (PABT) in New York City, the largest US bus terminal, were used to measure the occupancy rates for motorcoaches. Results on state-level bus occupancy rates are summarized. The paper concludes with guidelines for future data collection, validation, and training. The date, code, and user guide of this study can be found at an online GitHub repository.