I think your prof gave you an impossible assignment. Everything that has an impact on the community is controversial. Like someone in this country attacked a US senator for not raking their leaves. A project on a lack of sidewalks and public transit is really a project on the history of redlining, segregation, and environmental discrimination due to class and race.

I think if you write a good quality and well-researched paper on a controversial community problem that interests you, your prof will be forced to give you a passing grade. You could complain to the chair of the dept that you performed 300-level-work for a project with unreasonable expectations if she doesn't.