Risk Management

Give a few examples of how engineering and urban design can harden potential critical infrastructure targets.
What are transportation choke points, and what risks they pose to exposing passengers to attack?
In your opinion, what is the most vulnerable category of potential targets?
3-4 pages, plus title and reference pages (do not count towards page count). Conduct outside research, provide citations and references per APA. Opinions
should be supported by evidence and written in third person narrative.