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Home My WebLink About2018-08-21 Traffic Stop Power pointICPD TRAFFIC STOP ANALYSIS ICPD STOP MAP FBI Ridge Mail L��^ WYaterwarks Pr jr, Park C4) iG?c�5,r "r ,....�._ Zayre: 1 Zayre: 2 l Zayre: 3 Zayre: 9 5 Zonre: 6 Zonre: i Zmre: H g Coralville exn sr � s:. RC as SC ao JO 0: � k{ickory F4W Park s xr `pandrk n."� 1z Z. 91f Zayre: 10 �Zwre: 11 Zone: 12 SZ..: 13 Zone: 14 . Z.: 15 ......................... sa _ls� The University of lawn Universltyyof town H Iowa City Hospitals ilrrd Cl nits *a rr 5w : 17 2i zo..e: 1a :F44' Zone: 1 za 1,:, l t xiD zo..e: 22 r 011'2 st ire: 23 Lcu't Sr x9 Universr � „ Z�: .ZP •:: 3 sw Bent" St liurkwgod Ave � Ns-218 0Ari Z. 26..- �.� Z.- 77 t Zone: xe Zone: 29 Zone: Z.: �1 Zone: 32 0 9bW,'a City MkIFU � OR'[rpYt &tv0 rn ' Uft 21 k - Zwre: 33 Zwre: 34 Zone: 36 aw Z •— x.: ^35.•— : 39 ........ Zone: 441 a u Terryr Trueblocid �j Cdr, '.� Recrearrars Area s 6 sycamore Nt— r� x a SS sw I Ir Za : 41 Zor i4 Za : Si f ' : 44 ��. _ 45 dwre: 46 �J Zwre: 97 Z.- 5115 THE NUMBER OF ST ZONE Is 0 �C) 0- 0l7f 0 ^L, W Z C) Q N C� Number of Stops for Department rNM"ztMC [1-MMOrNMgtMCOMM(DO N M'tt M (0 [�- M M (D r C\J M M (0 [�- M M (Dqt M CDMNr,-OMM rrrrrrrrrrNNNNNNNNNNMMMMMMMMM��qj-M1.[)000000 Zone C. ti Z021919 z IM30 E3 Zt 77 IISL- Tura: 6 Hickory Hill Park Z.: 14 X Z.: 15 X gales P Z..: 22 Z026s Z021919 z IM30 E3 . .............. . s ------------ Z :a Z.: 32 Zane: 40 OSa'4' ZbOk 43 Z. -Mr G is Z..: 38 Zone: 29 Tefry 7 ruCl ..... . Rect ea (, w, arc 44 lr Zone: 45 40 Zone: 47 . .............. . s ------------ Z :a Z.: 32 Zane: 40 OSa'4' ZbOk 43 Z. -Mr Department Days Nights 12805 2595 10210 TRAFFIC OBSERVAm ►2015 traffic observations = 27,032 o. 2007-2012 traffic observations = 28,951 ► Total traffic observations = 55,983 TRAFFIC OBSERVATIONS 2007-2015 ►Zone 21 traffic observations = 11,880 ► Zone 29 traffic observations = 8.114 ► Other zones traffic observations = 7,038 ► Spread over zones 27, 28, 30 and 38 ► Observations made from 9/01/15 through 2/28/16 2015 OBSERVATIONS WE FOCUSED ON ZONES WHERE MOST STOPS WERE MADE Previous traffic stop observations and 2010 Census Bureau data suggest that about 10% of the drivers on the roads in most areas of Iowa City are minority drivers—both days and nights. 2015 traffic observations are most ► Percentage white ► Percentage African-American ► Percentage Hispanic/other ► Percentage Asian ► Percentage minority (total) ZONE 21 89.00% 04.00% 03.00% 04.00% 07.00 DAYS (DOWNTOWN AREA) ► Percentage white ► Percentage African-American ► Percentage Hispanic/other ► Percentage Asian ► Percentage minority (total) ZONE 21 74.00 16.00 02.00 08.00 18.00 NIGHTS (DOWNTOWN AREA) ► Percentage white ► Percentage African-American ► Percentage Hispanic/other ► Percentage Asian ► Percentage minority (total) 7 3.0 0 23.00 02.00 02.00 25.00 ZONE 29 DAYS (BROADWAY AREA) ► Percentage white ► Percentage African-American ► Percentage Hispanic/other ► Percentage Asian ► Percentage minority (total) 68.00% 31.00 01.00 170 < 01.00% 32.00 ZONE 29 NIGHTS (BROADWAY AREA) ► Percentage white ► Percentage African-American ► Percentage Hispanic/other ► Percentage Asian ► Percentage minority (total) ZONE 30 DAYS & NIGHTS 78.00 15.00 02.00 < 05.00% 17.00 ► Percentage white ► Percentage African-American ► Percentage Hispanic/other ► Percentage Asian ► Percentage minority (total) ZONE 28 DAYS & NIGHTS 86.00 13.00 < 01.00% < 01.00% 14.00 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 ► POLICE DATA 2016 DAYS 'go Number of Stops per Zone Days 0 0 N M rNM�Lf�CDf�OTNM�Lt�CDf�0000rNM�Lt�COf�0000rNLt�COf�0000CD00Lf� T r r r r r r r r N N N N N N N N N N M M M M M M M M�� SCO Zone W, N T W Percent of Minority Drivers Stopped and Benchmarks Days 0 13 20 21 22 27 28 29 30 Stops Percentage Benchmark Percentage ► The highest degrees of disproportionality tends to be concentrated in areas where the fewest stops were made ► A disparity index shows that the average degree of dispro areas of town was approximately benchmark values! han the corresponding ► The index gives a ballpark estimate of disproportionality. AVERAGE DISPARITY ACROSS ZONES NIGHTS O O O Number of Stops per Zone. Nights M VIVI�IV IV � Ullll 11 11 jll(IfDI(fII(01(I(i'MAU''AlAmmitiauu. . Percent Minority Drivers Stopped Benchmarks. Ights ► The highest degrees of disproportionality is concentrated in areas where the fewest stops were made ► A disparity index shows that the average degree of values. ir 00. ss all areas of town was approximately higher than the corresponding benchmark The index gives a ballpark estimate of disproportionality. AVERAGE DISPARITY ACROSS ZONES DEPARTMENT Is 0 �C) 0- 0l7f 0 ^L, W Z C) Q N C� Number of Stops for Department rNM"ztMC [1-MMOrNMgtMCOMM(DO N M'tt M (0 [�- M M (D r C\J M M (0 [�- M M (Dqt M CDMNr,-OMM rrrrrrrrrrNNNNNNNNNNMMMMMMMMM��qj-M1.[)000000 Zone Percentage of Minority Drivers Stopped and Benchmarks. All ► The highest degrees of disproportionality is concentrated in areas where the fewest stops were made ► A disparity index shows that the average degree of across all areas of town was approximately benchmark values! igher than the corresponding ► The index gives a ballpark estimate of disproportionality. AVERAGE DISPARITY ACROSS ZONES Assignment Days Nights Department Delta 5 pts. 5 pts. Stops 3,650 9,200 12.850 OFFICER LEVEL AN (% Minority / Min. Benchmark) : (% W&A / W&A Benchmark) 0 LO T 0 N 0 Q 0 O r O O Z 0 LO Com] 0 2 4 6 Disparity Index Median = 1.94 9W, Percentile = 2.88 W Median = 1.43 9W, percentile = 2.43 OUTCOMES ► (Minority-yes/Minority-no) : (White-yes/White-no) ► Values > 1 suggest disproportionality ODDS -RATIOS Time of Day Type of Violation Reason for Stop Area of Town Driver Simple OR = 0.67 minority white Total no yes 506 2,579 1,122 1,628 WARNINGS 8,455 11,034 Total 3,085 9,577 12,662 Multivariate OR= 0.72. (1.38) Simple OR = 1.29 no yes Total minority 29649 436 39085 white 89497 19080 99577 Total 119146 19516 129662 CITATIONS Multivariate OR = 1.38 Simple OR = 1.90 no yes Total minority 29770 315 39085 white 99037 540 99577 Total 119807 855 129662 ARRESTS Multivariate OR = 1.56 Simple OR = 1.90 no yes Total minority 29811 274 39085 white 99037 540 99577 Total 119807 855 129662 Multivariate OR = 1.55 For stops not including non -discretionary arrests NON -DISCRETIONARY ARRESTS OR = minority white Total 1.76 no yes Total 29770 41 29811 99037 76 99113 119807 117 11.924 DISCRETIONARY ARRESTS Multivariate OR = 1.54 Simple OR = 2.50 no yes Total minority 39049 36 39085 white 99542 45 99577 Total 129581 81 129662 SEARCH REQUESTS Multivariate OR = 2.15 OR=1.05 no yes Total minority 142 55 197 white 255 94 349 Total 397 149 546 H ITS citations 2011 2012 2013 2014 2015 arrests 2005 2006 2007 2010 2011 2012 2013 2014 2015 search requests 2005 2006 2007 2010 2011 2012 2013 2014 2015 2006 hit rates 2015 ,iff, 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. SUMMARY 2017 INFORMATIO C. ti Z021919 z IM30 E3 Zt 77 IISL- Tura: 6 Hickory Hill Park Z.: 14 X Z.: 15 X gales P Z..: 22 Z026s Z021919 z IM30 E3 . .............. . s ------------ Z :a Z.: 32 Zane: 40 OSa'4' ZbOk 43 Z. -Mr G is Z..: 38 Zone: 29 Tefry 7 ruCl ..... . Rect ea (, w, arc 44 lr Zone: 45 40 Zone: 47 . .............. . s ------------ Z :a Z.: 32 Zane: 40 OSa'4' ZbOk 43 Z. -Mr DAYS 750 500 0 U PKI] D Number of Stops by Zone -- Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1819 20 2122 23 24 25 26 27 28 29 30 31 32 34 35 36 37 38 39 40 4143 44 45 46 48 49 52 57 59 60 61 62 65 Zone Ilk -M v 0.2- .2 - 0.1- 0.1 - M ii Police Stops v Benchmarks -- Days 13 20 21 22 27 28 zone T 30 37 Legend ■ Benchmark ■ Police Stops C. ti Z021919 z IM30 E3 Zt 77 IISL- Tura: 6 Hickory Hill Park Z.: 14 X Z.: 15 X gales P Z..: 22 Z026s Z021919 z IM30 E3 . .............. . s ------------ Z :a Z.: 32 Zane: 40 OSa'4' ZbOk 43 Z. -Mr G is Z..: 38 Zone: 29 Tefry 7 ruCl ..... . Rect ea (, w, arc 44 lr Zone: 45 40 Zone: 47 . .............. . s ------------ Z :a Z.: 32 Zane: 40 OSa'4' ZbOk 43 Z. -Mr NIGHTS 4000 Number of Stops by Zone -- Nights C D 0 U 2000 1000 0 1 2 3 4 5 6 7 8 9 10 11 121314 15 16 17 18 19 20 2122 23 24 25 26 27 28 29 30 31 32 34 35 36 37 38 39 40 4143 44 45 46 48 49 52 57 59 60 6162 65 Zone 0.4- .4 - 0.3- 0.3 - Police Stops v Benchmarks -- Nights .-0.1 - M ii 13 20 21 22 27 28 zone 29 30 37 Legend ■ Police Stops ■ Benchmark C. ti Z021919 z IM30 E3 Zt 77 IISL- Tura: 6 Hickory Hill Park Z.: 14 X Z.: 15 X gales P Z..: 22 Z026s Z021919 z IM30 E3 . .............. . s ------------ Z :a Z.: 32 Zane: 40 OSa'4' ZbOk 43 Z. -Mr G is Z..: 38 Zone: 29 Tefry 7 ruCl ..... . Rect ea (, w, arc 44 lr Zone: 45 40 Zone: 47 . .............. . s ------------ Z :a Z.: 32 Zane: 40 OSa'4' ZbOk 43 Z. -Mr INDIVIDUAL OFFIC DISPROPORTIONA z O 1000 500 X -4-- Officer Index Values 1 2 3 4 Index Pin Index Stops 11 4.43 257 14 4.03 34 30 3.50 524 63 3.26 92 58 3.16 91 OUTCOMES OVER �0 -1 Citations Odds -Ratios 2005 2006 2007 2010 2011 2012 2013 2014 2015 2016 2017 Year 3 2 0 Arrests Odds -Ratios 2005 2006 2007 2010 2011 2012 2013 2014 2015 2016 2017 Year 0 2 0 Search Requests Odds -Ratios 2005 2006 2007 2010 2011 2012 2013 2014 2015 2016 2017 Year 2 0 -1 -2 -3 2005 2006 Hit Rates Odds -Ratios 2007 2010 2011 2012 2013 2014 2015 2016 2017 Year ➢ Disproportionality in most stop outcomes decreased in recent years. The single exception was arrests, where disproportionality slightly increased. ➢ In 2017 officers requested to search a vehicle less than twenty times. This is a notable reduction from previous years. ➢ Overall, results suggest that the levels of disproportionality in stops and outcomes is trending lower. ➢ 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 v considerably higher than other officers' values.