"I'm alerting you to an "app" which allows easy complaints to NYC Agencies (not all, but enough). It is: NYC 311.
It very simply allows one to file complaints about various issues within the city of NY.
I have used this to complain about Sidewalk parking outside the Jamaica Center Subway station on Archer Avenue. Additionally, I've filed complaints on the MTA Web Site, and the Parks Department Web site (Why Parks, well these idiot parkers park in the TREE PIT...).
All complaints emphasized Illegality of Parking, Safety and Problems with Accessibility (ADA Complaints).
Complaints were also filed on MTA web site (mta.info, http://web.mta.info/faqs.htm, email...) to file complaints.
I believe that sidewalks BLOCKED with DREK (Cars, Garbage, whatever,...) constitute ADA violations which get taken more seriously than just a blocked sidewalk. While I am a HUGE Former Division I Football Player, I was seriously disabled in 2013 and confined to a wheelchair, the walker, then cane(s) and personally felt the problem of DREK blocked sidewalks, including the ILLEGAL cars parked at Jamaica Center.