These systems are pretty good at detecting fire crackers and backfiring cars. E.g., check out this recent map of results: http://www.minneapolismn.gov/www/grou

These systems are pretty good at detecting fire crackers and backfiring cars. E.g., check out this recent map of results: http://www.minneapolismn.gov/www/groups/public/@mpd/documents/webcontent/wcms1p-116173.pdf http://www.minneapolismn.gov/www/groups/public/@mpd/document... Only a few of those points are actually shootings.