Greatings Gents and Ladies; My impression is that a BOB/Bug out Bag is just as the name implies; a bag with the supplies necessary to sustain life for up to 24 Hrs. when you need to get out of Dodge NOW. Short duration equipped due to the need for light and fast. If needed to stretch longer then 24 hrs, then contents must be suplimented from external sources. 72 Hr. bag as the name implies, is for the situation where your either forced from home, or are more then 2 days walk from home. Due to increased requirements for tools and supplies, it is not as "fast" as BOB, but to my mind must still be portable over extended distances. A truck/ car bag might be a collection of additional supplies ( extra clothes, food, water) to supliment Bob or 72Hr., or for if you were to be stranded in your truck or have access to your vehicle after an event. Either BOB or 72Hr. or both can live in your car. Bob can be an extension of your EDC, and as such be your constant companion while 72Hr. waits in the truck. Comments? Thanks; Jim