This still comes back to a means test of some variety. For your example with vehicles, if you possess the means to not require a large vehicle (such as being single or having a small family), then you would obviously be allocated the smaller vehicle. This is vastly simplified than what such a thing would likely look like in reality. For govt assistance in the US for example this usually begins with your income level.

On a separate note, I'm still very curious of your answer to my question referring to the source.