Columbia Business School
Revised December 18, 2000

The New York City Police Department Patrol System
The City of New York is divided into 73 precincts. These precincts are the basic managerial units for the operation of the familiar police patrol cars (called radio mobile patrols or RMPs) we see on the City streets. For staffing purposes the Police Department divides the day into three eight-hour tours of duty: 12 midnight to 8AM, 8AM to 4PM, and 4PM to 12 midnight. A particular police precinct such as the 26th, in which Columbia University stands, may have 6 patrol cars in the field during the typical 8-to-4 tour. In New York about 1200 cartours are fielded on an average day -- about 200 on the 12 to 8 tour, about 400 on the 8 to 4 …show more content…
Fortunately, accurate data is readily available from the 911 computer system which records detailed information about each call. The table below illustrates the type of data that is collected and used to help determine allocations for each 8 hour tour of duty. Though at any given point in time the total number of RMP’s is fixed, occasionally the city decides to either increase or cut the number, usually as a reflection of the financial status of the city. The marginal cost of adding a fully staffed car for one tour-of-duty for a year is approximately $300,000 ($230,000 of which is for labor). Suppose the city consists of only six precincts as shown in the table. Your assignment is to allocate patrol cars among these six precincts for the tour of duty described by these data. You may assume that, on average, a car spends 30 minutes on each call in each precinct. Furthermore, statistical analysis has shown that service times are well modeled by an exponential distribution.

NYPD Patrol System Columbia Business School

p.2 © 1998, Linda V. Green

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PRECINCT

AVERAGE NO. CALLS/ HOUR 6.4 3.8

PERCENT OF CALLS HIGH PRIORITY 8.2 7.7

TOTAL FELONIES PER YEAR 10,600 6,600

SIZE (SQ. MI.) 1.9 .8

A B

C D E F

2.6 3.4 1.5 6.6

7.3 13.8 4.0 12.2

4,300 9,400 1,800 8,500

5.2 1.0 17.0 1.7

NYPD Patrol System Columbia Business School