Have extra trunk space that takes up car space, so if you don't bring followers with you, you can carry more stuff. Whether that's the bed of a truck, or the front passenger seat of your car. The 1-5 spaces that would be reserved for players or NPCs can now be used for a fat rucksack instead.
This will lead to situations where you may have to choose between a friend or resources. Resources that might save several friends, if you get it back. It can also give you a good reason not to bring backup on a dangerous expedition-- more loot instead of more help. Smaller communities also benefit for being minimalist, and larger communities pay the price in more than just food upkeep.