As you have heard, the car is everyone's. The entire village loves it. Kids ride it, the postman does his beat in it, atleast one corpse is transported on its roof, infants are delivered in it and what not.
But, while the film does make the most out of a - weakened by overuse - Tamil film trope: 'the good, simple people of the village' , what makes it special is that, it engages with the touchy question of 'ownership' quite well. The film is particular about acknowledging the sense of unease in precisely what is not articulated: that the car is not everyone's. It IS private property after all. And that there are degrees of ownership and claims that each have over it and which they want to defend against the claim of an 'other' - an other perceived as an outsider with a lesser claim. Or an other having a greater claim, which makes one insecure. Or an other having without deserving, a greater claim.