The term "survival kit" may also refer to the larger, portable survival kits prepared by survivalists, called "bug-out bags" (BOBs), "Personal Emergency Relocation Kits" (PERKs) or "get out of Dodge" (GOOD) kits, which are packed into backpacks, or even duffel bags. These kits are designed specifically to be more easily carried by the individual in case alternate forms of transportation are unavailable or impossible to use.
Say you're at work and a terrorist attack occurs. Roads are closed to any and all traffic but you only want to get home - even if that means walking. You may not want to grab your full on family pack in the car or you may not even be able to get to it. But you just want a light kit to get you through. How far is it to get home from wherever you may be? This get home kit should provide for 1-3 nights of traveling on foot till you make it home.