Seeking to end more than two weeks of a precipitous drop in police activity, Police Commissioner William J. Bratton said on Friday that he had instructed top commanders to do what they could to reverse the trend.
The message, which was delivered to union leaders on Wednesday and to commanders over the next two days, was relayed to rank-and-file officers during roll calls on Friday, according to people familiar with the discussions; one supervisor said that officers were told to “start working again.”
It appeared that the message had gotten through.
“The slowdown is over in the sense that the numbers are starting to go back up again,” Mr. Bratton told reporters on Friday. “I anticipate by early next week that the numbers will return to their normalcy.”
Mr. Bratton said he would not release the precise number of arrests and summonses until Monday.
In the courts on Friday, the number of people being arraigned on criminal charges had doubled compared with earlier in the week, but had still not reached normal levels. As courts opened, 479 people arrested on Jan. 8 were waiting to see a judge, compared with 212 arraigned citywide on Jan. 2.
On the streets, traffic agents were expected to start writing more summonses since they were told earlier this week that they would no longer be doubling up, said Robert Cassar, the head of the union representing them.
“Cops have all heard it at roll call,” said the supervisor, who asked to remain anonymous because he was not permitted to discuss the matter. “The word is out: You better start working again.”
For two weeks, police officers have sharply cut back on making arrests and issuing summonses, particularly in more discretionary activities. In the seven days through Sunday, officers made a total of 2,401 arrests, compared with 5,448 for the same week the last year, a 56 percent decline; 347 criminal summonses were issued in that period, down from 4,077 a year ago. Parking and traffic tickets dropped by more than 90 percent in the same period.
Mr. Bratton, nonetheless, said he could not characterize the phenomenon as an organized work stoppage. In recent days, he has preferred to wrap the impetus for the declines in a bevy of possibilities: the large-scale protests over police practices last month; the mourning period for two Brooklyn officers fatally shot on Dec. 20; a dip in 911 calls.
“I don’t know what the cause is,” Mr. Bratton said on Friday. “That’s 30,000-some-odd officers; that their motivations might be different for different ones.” He added: “I’m not aware of any formal encouragement by union leadership in this matter.”
Throughout the two weeks, he said, certain platoons and precincts had lower activity than others. He said he would be putting “management attention” on areas that saw the steepest drops, including in transit, housing and highway enforcement. “We have been very carefully identifying where we have issues that would require closer supervision,” he said.
At the same time, he stressed that he was “not driving activity levels” or demanding officers generate a certain level of numbers.
The first missive from Mr. Bratton came during a closed-door meeting on Wednesday with police union leaders; he told them that he expected the drop in summonses and arrests to soon reverse itself, a person familiar with the meeting said. They could not underestimate, Mr. Bratton stressed, how less than vigorous street work could create a lawless climate, another person familiar with the meeting said. Both people asked to remain anonymous because of the sensitive nature of the topic.
Mr. Bratton would not discuss what was said at the meeting except to say, “The unions fully understand from me what my expectations are, and that cops, basically, are paid to work and that I expect that they’re going to work.”
On Thursday, at a meeting in Police Headquarters, Mr. Bratton delivered a message to commanders from southern Brooklyn that he expected them to share with colleagues in all five boroughs: Rank-and-file officers have a job to do and captains and inspectors must ensure they do it. He told borough commanders the same thing on Friday.
However, a review of charges lodged against the first batch of people arraigned in Manhattan on Friday showed very few of the minor quality-of-life charges that usually fill the calendar, such as fare-beating or lying on a subway car’s bench. The most common charges were third-degree assault and petty larceny.
With any combination of factors at play, the numbers could yet be affected by events.
Mr. Cassar, the head of the traffic agents’ union, said weather could never be discounted: On Friday, a larger-than-expected snowfall and a flip-flop on alternate-side parking regulations might have stymied even the sternest orders for activity.
“We are not supposed to clean off people’s cars in order to see their registration,” he said. “Any kind of inclement weather has an effect on summons productivity. In winter months, summons activity usually goes down.”
James C. McKinley Jr. contributed reporting.