If I remember correctly, one of the devs said that vehicles don't have gas caps because it's way easier to mirror the UV map (for making skins) that way
because there are no drivers this is a sim, not GTA also i think gascaps are not coming in the future, @Noah Polter
That might be the case, but there should honestly be gas caps. Out of all of the strange missing features from vehicles, the lack of gas caps even though we have gas stations drives me insane.
Airbags and PEGI are not related. Airbags are related to being too complex physics for something so minor.
Lovely idea, I would love to see those implemented ! A good modder can make those too I believe, the fuel cap being little easier then the airbag, but from what I myself learned to do with this game in a few months of time I find myself believing that almost anything is possible here. Even without too much complexity or memory consumption IF one thinks things thru thoroughly.