Some cities in the US just make it illegal to be homeless. Problem solved.
1. No public transportation.
2. Unreasonable distances between gathering places (e.g. grocery stores) and often long stretches of no sidewalks.
3. Public park curfews with police sweeps of said parks at night.
No way to get in, no way to get food, no way to stay. When I realized, as a teenager, that this was why I was not used to homeless people, I was a little perturbed.