To answer the question a bit more practically, public housing projects ('caserÃos') are readily identifiable in Puerto Rico, usually consisting of many, medium-rise buildings, all painted the same color, and often on controlled access streets. Here is an example: . You can often even see a caserÃo on Google Maps (). You won't just wander into one. On the other hand, in the metro area areas relatively nearby caserÃos are not necessarily bad areas. For instance Ocean Park & Isla Verde (very safe) are both very close to the Llorens housing project, which is generally considered unsafe.