That 10 billion of car ad spend per year adds up.
Those have nothing to do with investing in public transportation.
Your agenda is showing, lay off the NewsMax, my friend.
Assuming your anecdote is 100% absolutely positively true and not made up at all, and that you actually saw kids get stuck with needles and die, here's the rub: your anecdote doesn't matter.
Your argument is literally: the solution to homeless and drug addiction is ... better manners?
Do you expect people to take you seriously?
America offers various lifestyles, from big cities like NYC, Boston, etc where a car is a liability, to near suburbs that are well served by transit (eg, NYC tri-state area) where you probably need a car but your daily commute doesn't involve it, to more spread-out and rural living where car is absolutely necessary.
This speaks to a trade-off between density and car-dependence. People across the globe face similar trade-offs (eg: 50% of Dutch persons own a car, 86% of French households do...)
[1] https://frontiergroup.org/resources/fact-file-americans-driv...
On the other hand: https://old.reddit.com/r/fuckcars
And busses, light rail, intercity trains.
But America associates one-car-per-person with all kinds of twisted politics and self-esteem anxiety.
We need a psyops program to wean people off cars, and it will take a decade or more. Just look at the anger in any HN thread that is critical of cars, it runs deep.