Payload is ultimately GVWR - gross vehicle weight. If GVWR is 5,000lbs, vehicle is 4,000lbs, you can add another 1,000lbs. If you have 150lb driver you have 5000-4000-150. If you have a 250lb driver, it's 5000-4000-250.
Yea I guess I did so I'm changing my question has anyone seen payload specs for any vehicle where a 150 lb driver is excluded and maybe another 150 lb passenger.
I guess I was assuming that payload calculations had some sort DOT regulations.
Some placards and ratings assume a certain driver/passenger/fluid weight, but it is ultimately as simple as GVWR - "put the vehicle on a scale with whatever people, tools, and other stuff you want" = remaining payload.