VEHICLE STOPS

Vehicle stops refer to when an officer stopped a member of the public who was driving.

VEHICLE STOPS BY RACIAL GROUP

What does this show?

Each bar on the right shows the percentage of the total stops recorded each year that were people of one racial group. The bars to the left, and the dotted line, show the average percentage of stops recorded for each racial group for the entire report period. Hovering over a bar shows the number of stops that makes up that percentage.

Unlike the analyses conducted for pedestrian stops and use of force incidents, CPE does not directly compare vehicle stops to local demographics. This is because local driving populations may include non-resident drivers who may have a different racial makeup than local Census data. However, if the share of people stopped while driving differs significantly from the resident population, the difference is likely not fully explained by a different racial makeup of non-resident drivers. It may indicate that there are racial disparities in vehicle stops due to police behaviors or policies.

How was this calculated?

We took the average number of stops recorded per year and calculated the percentage of stops that were made of people of each racial group. See the Data Notes tab for information on how we define racial groups.

We measure a vehicle stop as a single record of a driver being stopped by police, regardless of the number of officers or passengers involved. We recognize that departments may collect vehicle stop data in other ways (for example, not distinguishing between searches of drivers and passengers). Our guidance on collecting data has more information on how to effectively report vehicle stops.

We generally use all vehicle stops data provided by departments, including incomplete years of data. However, certain analyses require complete years of data, so time periods may vary across charts.

 

Data required for this analysis:

To arrive at this finding, we first looked at the total number of vehicle stops made in each year. Note that this assessment analyzes vehicle stop data from January 16, 2018 to December 26, 2020.

The total number of vehicle stops recorded each year varied from a high of 1,970 in 2019 to a low of 809 in 2020.

COMPARING SEARCH RATES AT VEHICLE STOPS

What does this show?

This visualization shows, out of the same number of stopped drivers, how many drivers in each racial group were then searched.

How was this calculated?

We first divided the number of stops that involved a search for each racial group by the number of stops of that racial group. We then multiplied that number by 100 to get the per 100 stops rate.

See the Data Notes tab for information on how we define racial groups.

 

Data required for this analysis:

CONTRABAND FOUND AND NOT FOUND IN VEHICLE STOP SEARCHES

What does this show?

One common explanation for why members of some racial groups are stopped or searched at different rates is that they may be more likely to have contraband. To assess this, we looked at whether searches of drivers of different racial groups resulted in contraband being found at different rates. For each racial group, we separated all searches into the percentage that resulted in contraband found and the percentage that resulted in no contraband found.

The darker portion of each bar (on the bottom) shows the percentage of all searches of drivers of that racial group that ended with contraband found, while the lighter portion of the bar (at the top) shows the percentage where no contraband was found. Hovering over a bar shows the number of searches that makes up that percentage. Each bar at the top shows the total number of searches recorded for that racial group.

It is important to compare this chart to the percentage of vehicle stops of each racial group, above, to identify which groups may be experiencing a high volume of stops that may be driving high totals of contraband found.

How was this calculated?

We took the total recorded searches of drivers of each racial group and calculated the percentage that did and did not reveal contraband. Police are typically required to search people they arrest and vehicles they impound or tow. When the search reason is provided in the LEA’s data, these searches are excluded from this analysis because they are not necessarily based on an officer’s discretionary evaluation of whether they expect to find contraband.

See the Data Notes tab for information on how we define racial groups.

Data required for this analysis:

VEHICLE STOP REASONS BY RACIAL GROUP

What does this show?

Each colored bar shows the percentage of all stops of drivers of that racial group for which that stop reason was recorded. Hovering over a colored bar shows the number of stops that make up that percentage. Each gray bar on the right shows the total number of stops that were made for a given reason. Any stop reason that was recorded in a high number of stops, or that has large disparities, will influence the racial makeup of vehicle stops overall.

How was this calculated?

We took the total recorded stops of drivers of each racial group and calculated the percentage made for each reason. We then grouped these percentages according to stop reason.

We combine categories of reasons for easier interpretation. See the Data Notes tab for details on how these categories are created and how racial groups are defined.

Data required for this analysis:

VEHICLE STOP OUTCOMES BY RACIAL GROUP

What does this show?

Each colored bar shows the percentage of all stops of drivers of that racial group for which that stop outcome was recorded. Hovering over a bar shows the number of stops that makes up that percentage. Each gray bar shows the total number of stops for which that stop outcome was recorded.

How was this calculated?

We took the total recorded stops of drivers in each racial group and calculated the percentages for which each enforcement outcome was recorded. We then grouped these percentages according to enforcement outcome.

We combine categories of reasons for easier interpretation. See the Data Notes tab for details on how these categories are created and how racial groups are defined.

Data required for this analysis:

VEHICLE STOPS BY WORK UNIT AND RACIAL GROUP

Among all work units:

What does this show?

“Work unit” describes the work groups within a department. It can refer to the assignment of the officer making the stop (e.g. Detective Unit, Narcotics, Traffic, etc.), or the geographic areas where stops are made (i.e. precincts, districts, zones, etc.).

Each colored bar shows the percentage of stops recorded by each work unit of drivers of each racial group. The Multiple Work Units category, if used, represents stops involving officers from two or more work units. Hovering over a bar shows the number of stops that make up that percentage. The grey bars on the right show the total number of stops recorded by each work unit. Any work unit that records a large number of stops or records large racial disparities will influence overall racial disparities in vehicle searches. If disparities are present among most work units, or are severe in some work units, the different racial makeup of various neighborhoods is likely not the whole explanation for the observed disparity.

How was this calculated?

We took the total recorded stops and first separated them by the work unit that made the stop. We then calculated what percentage was recorded for people of each racial group.

The “Other Work Units” category, if used, combines the work units recording less than 2% of stops. See the Data Notes tab for information on how we define racial groups.

Data required for this analysis:

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