Defying expectations, the NYPD drove crime down to record levels. This is the result of intense crime-fighting, made successful by innovative policing strategies and difficult work by cops. But policing challenges, old and new, are still with us.

Shootings and killings, also around record lows but seeing recent upticks, continue to test the NYPD. Terrorism is a constant threat. Some neighborhoods aren't as safe as others, and they require additional policing resources. And we must acknowledge the unsteady relationships between police and some communities -- friction that makes it more difficult to protect those neighborhoods.

To address those challenges, we must shift how we police. This requires two priorities: Maintain low crime (including anti-terror efforts), and improve the police-community relationship. Both require investment, including personnel.

Yet the police department has far-fewer officers on-hand than it did at the beginning of the century to handle a broader mandate. With a reduction in force size from 39,000 in 2001 to less than 35,000 today, the NYPD is left squeezing its resources at a critical moment.

Help is needed. Adding the 1,000 new officers proposed by the City Council would be a good start. Mayor Bill de Blasio was also wise to propose more funding for an effort by Commissioner Bill Bratton to train cops in community relations. That should also be added to next year's budget.

But retraining is not enough. Effective community engagement will take more time, and the size of the current force is inadequate. In this new era of policing, cops will simultaneously need to cover the streets of a neighborhood and its community meetings to address local issues.

Some say there is already too large a police presence in those neighborhoods, but what is really needed are more cops who can work with the community on preventing crime, as well as responding to it.

For all of these reasons, police must evolve to connect with the public like never before. Though crime is lower, the challenges of a modern department are more complicated.

That will take a renewed commitment of resources by our government, including the 1,000 new officers proposed by the City Council.

Richard Aborn is the president of the Citizens Crime Commission of New York City.