I was always told that searching, finding, and processing your data [for a GIS project] is 80% of the work. That's the tough part. As a grad student, researching and finding data sources will be a necessary and essential task you'll need to master.
That said, you're looking for "open data." Just type in a few combinations of what you're looking for on Google ("traffic deaths") with the words "open data" or "open data portal" and you'll get closer to what you want. A few US cities have opened up data like this. I don't want to totally give away the answer for ethical reasons, but hopefully this will help. ;)
Scraping from Google Maps and that sort of thing takes some coding experience to get it done reasonably. Start with open data portals for now!