The idea behind neighborhood policing is pretty simple: The same cops walk the same beat day in and day out getting to know the New Yorkers who live and work in the area they patrol.

Now that same back-to-basics approach will go underground.

"We are the safest big city in America but we will get safer," De Blasio said.

The neighborhood police officers will join the NYPD cops who already patrol the subway system. The rollout is starting in downtown Brooklyn and other parts of the borough and in the south and central Bronx with a total of 12 neighborhood officers riding the rails and patrolling stations.

Signs will be going up explaining the program - with the names and email addresses for the neighborhood police officers. But the extra police - while welcome by some - will do nothing to address the frequent delays and breakdowns on the subway system.

"Yeah, we all need to do a lot to continue our efforts to fix the subways but safety comes first I think the notion that you are going to have a police officer you get to know personally. That you are going to have an email, you can email them directly if you have a concern, I think that is going to be very reassuring to people," De Blasio said.

The mayor says officers will also be reaching out to homeless people underground - trying to get them into shelter or connect them with services.

"The goal is, win the trust. Get the person in off the street, keep them off the street. So I think this kind of approach which really emphasizes the human connection is really going to help quite a bit," De Blasio said.

The underground neighborhood policing program is set to expand across the city by the beginning of next year.