- Is there evidence of (racial) inequity in the amount of traffic stops by police?
- Attach this analysis with broader demographics in each state/region - how likely is a traffic stop for a random person based on demographics? For what reason?
- Working paper: https://5harad.com/papers/traffic-stops.pdf
- Data source: https://openpolicing.stanford.edu/data/
- Visualization Inspiration: https://www.nytimes.com/interactive/2018/03/19/upshot/race-class-white-and-black-men.html
- More than 60 million (63.7) state patrol stops
- 20 States
- Between 2011-2015
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Quantify racial disparities in stop rates and post-stop outcomes Black drivers stopped more often than White relative to driving-age population, but Hispanic drivers stopped less often than White... Black and Hispanic drivers more likely to be ticketed, searched, and arrested
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Investigate the degree to which these differences may result from discrimination - focusing on search decisions Bar for searching Black and Hispanic drivers is lower than searching White drivers
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Effects of drug policy on stop outcomes Legalization of recreational weed in WA and CO reduced search and misdemeanor rates across the board, though relative race gap still exists
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stop_rate: "the rate at which white, black, and Hispanic drivers are stopped, relative to their share of the driving-age population" (p. 4). driving-age population is readily available, accurately estimated by US Census bureau, doesn't take into account race-specific differences in driving behavior (I am ok with this) (Figure 2, pg. 4) โ โ * https://github.com/5harad/openpolicing/blob/master/results/data_for_figures/fig2_stop_rate_county.csv.
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speeding citation rate?: "the probability a driver stopped for speeding is given a citation as opposed to a warning (or no penalty at all) - (p. 6)"
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search_rate: Likelihood of getting searched for drugs, weapons, contraband after you're stopped. 2% white, 3.5% black, 3.8% hispanic (p. 6)
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consent searches: officers must seek permission from drivers to search their vehicles - probable cause searches don't need consent but have a higher standard of evidence.
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arrest rates: % of stops resulting in the arrest of the drivers (p. 7)
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hit rate: The proportion of searches that successfully turn up contraband (p. 8) - nine states include race, location of stop, search, and contraband found fields. Hispanic hit rates lower than whites (22%), white=black rates (28%) (a lower hit rate means more discrimination, since this suggests double standard of searching more on less evidence)
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threshold test: In effect, what is the "threshold" of suspiciousness that an officer has when evaluating whether to search a driver. A higher threshold = more trust, so a lower threshold shows more bias, which will require some though on how to actually visualize this in the context of more drivers - maybe using that threshold.