"Interior volume" refers to the total space or capacity within a specific area, such as the inside of a building or a room. It measures how much room is available inside the enclosed space. Full definition
The Regular cab offers two options for box length and up to 8 feet for bed length, while providing the same amount of total interior volume. (hendersonvilleram.com)
Inside there's more interior volume thanks to the increased length. (thetorquereport.com)
Both the sedan and the hatch offer seating for five with class - leading interior volume for extra passenger comfort and cargo - carrying capability. (driving.ca)