HomeMy WebLinkAbout ICPD PresentationICPD TRAFFIC STOP ANALYSIS 2018
ICPD STOP MAP
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THE NUMBER OF STOPS BY ZONE
Number of stop
department = I
4000-
2000
o - --o❑oma❑
Number of Stops in Each Zone -- Department
❑0-- - ----❑
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 35 36 37 38 39 40 41 44 45 46 48 52 60 63 65
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NUMBER OF STOPS 2018
Department
Days
Nights
12,349
2,957
9,392
TRAFFIC OBSERVATIONS
TRAFFIC OBSERVATIONS 2007-2015
2018 traffic observations = 54,218
2015 traffic observations = 27,032
2007-2012 traffic observations = 28,951
Total traffic observations = 1 10,201
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ZONES WHERE OBSERVATIONS WERE
CONCENTRATED
Zone 13
Zone 19
Zone 20
Zone 21
Zone 22
Zone 27
Zone 28
Zone 29
Zone 30
Zone 37
Zone 38
BENCHMARK VALUES
Zone
Days
Nights
13
0.10
0.10
19
0.12
0.12
20
0.10
0.10
21
0.10
0.18
22 0.10 0.10
27 0.14 0.14
28 0.14 0.14
29 0.25 0.32
30 0.20 0.20
37 0.10 0.10
38 0.12 0.12
A WORD ABOUT THE BENCHMARKS
Please keep in mind that roadside observations are
simply a sample of the drivers on the roads.As such, the
values indicated in the results should be treated as
estimates with a fairly generous confidence interval
Previous traffic stop observations and 2010 Census
Bureau data suggest that in areas outside observation
zones, about 10% of the drivers on the roads are
minority drivers—both days and nights.
POLICE DATA 2018
DEPARTMENT
Number of stop
department = I
4000-
2000
o - --o❑oma❑
Number of Stops in Each Zone -- Department
❑0-- - ----❑
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 35 36 37 38 39 40 41 44 45 46 48 52 60 63 65
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Police Stops v Benchmarks -- Department
Index = 0.07
0.3 -
0.2 -
ca
Legend
C
y . Benchmark
v
y ■ Police Stops
C�.
0.1 -
0.0 -
0 13 19 20 21 22 27 28 29 30 37 38
zone in
DAYS
800- Number of stops
days = 2957
600-
O
400 -
200-
0- ®—o11❑❑
Number of Stops in Each Zone -- Days
J J�o_o�oo�oo
1 2 3 4 5 6 7 8 9 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26 27 28 29 30 31 32 33 35 36 37 38 39 40 44 45 46 52 63 65
Contact.Zone
Police Stops v Benchmarks -- Days
Index = 0.057
0.2 -
Legend
■
Vd
Benchmark
Cd
■ Police Stops
0.1
0.0 -
13 19 20 21 22 27 28 29 30 37 38
zone in
NIGHTS
Number of Stops in Each Zone -- Nights
Number of
4000- stops nights
= 9392
3000-
000-
2000-
2000`
1000
1000
0----❑oo0--°o O
1 2 3 4 5 6 7 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 35 36 37 38 39 40 41 44 45 46 48 52 60 63 65
Contact -Zone
Police Stops v Benchmarks -- Nights
Index = 0.092
0.4 -
0.3 -
a
Legend
J ■ Benchmark
J
0.2
■ Police Stops
0.1 -
0.0 -
0 13 19 20 21 22 27 28 29 30 37 38
zone in
OFFICER LEVEL ANALYSIS
DISPARITY INDEX
(% Minority / Min. Benchmark) : (% W&A / W&A Benchmark)
2018 INDIVIDUAL OFFICER RESULTS
1 500
1000
500
Officer Index Values
1
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1
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1
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1
0
2
Index Values
4
2017 INDIVIDUAL OFFICER RESULTS
z
1500
1000
500
0
Officer Index Values
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0 2 4
Index Values
2016 INDIVIDUAL OFFICER RESULTS
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Disparity Index
OUTCOMES
ODDS -RATIOS
Compares the values of two ratios
(Minority-yes/Minority-no) : (White-yes/White-no)
Values > I suggest disproportionality
CITATIONS
Simple OR = 1.005 no yes Total
minority
2,630
395
3,025
white
8,112
1,212
9,324
Total 10,742 1,607 12,349
Simple OR = 1.98
ARRESTS (ALL)
no yes Total
minority 2,754 271 3,025
white 8,882 441 9,324
Total 11,637 712 12,349
ARRESTS (DISCRETIONARY)
Simple OR = 1.307 no yes Total
minority 3,001 22 3,023
white 9,271 52 9,323
Total 12,272 74 12,346
NON -DISCRETIONARY ARRESTS
Simple OR = 2.04
no yes Total
minority 2,776 247 3,023
white 8,934 389 9,323
Total 11,710 636 12,346
Simple OR = 2.45
PROBABLE CAUSE SEARCHES
no yes Total
minority 2,906 119 3,025
white 9,171 153 9,324
Total 12,077 272 12,349
HITS
OR= 0.46 [2.16]) no yes Total
minority 61 58
white 50 103
Total 111 161
119
153
272
2017
2018
1.07
1.0
1.82
1.98
SUMMARY
Results suggest a degree of racial disproportionality in traffic stops conducted by
the ICPD. A ballpark estimate of the level of disproportionality indicates that
minority drivers were stopped on average about eight percentage points higher
than the observation benchmark values.
Comparatively little traffic stop disproportionality was found in areas of town
where the lion's share of traffic stops were made. Most disproportionality
occurred in areas where stops were less frequent.
Individual officer analyses show that one individual officers' disparity index values
were considerably higher than other officers' values.
SUMMARY
Disproportionality in most stop outcomes decreased in recent years. The single
exception was citations, where disproportionality increased. It should be noted
however, that odds -ratio values for citations were comparatively modest.
During 2016, disproportionality in arrests decreased.
In recent years, officers were about twice as likely to request a voluntary search
from a minority driver as from other drivers. This occurred even though seizures
or hit rates resulting from voluntary searches was about the same for minority
and non -minority drivers.
Overall, results suggest that the levels of disproportionality in stops and outcomes
is trending lower.