Police Commissioner Bratton says his department has a so-called peace dividend in communities of color, and he credits reduced enforcement in part for that phenomenon. NY1's Dean Meminger reports on what some local professors found when they looked at the numbers.

It's a dramatic shift by the NYPD. The number of arrests, summonses and stop-and-frisks is way down.

"They are carrying out the exact type of enforcement actions that they need to without touching a lot, a lot, a lot of citizens," said Richard Aborn, of the Citizens Crime Commission.

John Jay College of Criminal Justice studied enforcement activities by the cops. And found a 31% decline in four years — from an average of 7,200 enforcements a day in 2011, to just 5,000 a day last year.

"While these numbers have been going down, crime has stayed relatively stable," said Preeti Chauhan, assistant professor of psychology. "So, that brings into question do we need high enforcement activity to keep crime down."

The steepest reduction occurred in the number of stop-and-frisks — from a record of nearly 700,000 in 2011, to 50,000 last year. Summonses for minor violations are down too, by almost 200,000 a year.

Researchers say black and Latino young men, who were often targeted with aggressive enforcement, are most impacted by the declines. 

"Questions for New Yorkers, right now: 'Is this the new normal, is this the new expectation that we have about the interactions between police and citizens?'" said John Jay President Jeremy Travis

Young men who go here to John Jay say it's a good thing that there is less enforcement, but they don't want cops to go easy on hardcore criminals.

"I know there are certain cops that they want to do their jobs rightfully, but there are certain cops that just want to have that power," one student said. "They want to mess with you, frisk you for no reason."

"I would get pulled over for no reason," another student said. "They would say it was a mandatory check up. I don't see that happening now."

John Jay's president says reducing enforcement of low-level offenses can improve police community relations.

"The relationships between the police and particular the African-American community are centuries of difficult, problematic, tense, often violent interactions," Travis said.

Memories he says can't be erased in a few years, but he says that doesn't negate the importance of recent enforcement declines.