It's a very poor idea
First of all, we have quite enough government programs, thank you very much. Secondly, isn't it enough that I provide the tax dollars so people can have a place to live, electricity, food, clothing, children and medical.....all while also providing myself with those things? Now you want me to help the poor buy a car?
What, pray tell, do you plan to do with the millions of cars that would be ditched?