TRAFFIC STOPS

This section examines traffic stops, which are stops for which the recorded reason was “traffic violation.”

TRAFFIC STOPS BY RACIAL GROUP

According to Los Angeles County Sheriff’s Department West Hollywood Station data on traffic stops recorded between 2018 and 2021:

This analysis does not directly compare traffic stops to local demographics because the local driving population is more likely than the pedestrian population to include commuters and other non-resident people that 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, it may indicate that there are racial disparities in traffic stops due to police behaviors or policies.

What does this show?

Each bar in the first column shows the average percentage of stops recorded for each racial group during the entire assessment period. The bars in each of the following columns show the percentages of stops recorded for each racial group during each year of the assessment period. Hovering over a bar shows the number of stops that makes up that percentage.

 

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 traffic 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 traffic stop data in other ways (for example, not distinguishing between searches of people and passengers). Our guidance on collecting data has more information on how to effectively report traffic stops.

We generally use all traffic 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:

The total number of traffic stops recorded each year with complete data varied from a high of 5,943 in 2019 to a low of 1,735 in 2020.

COMPARING SEARCH RATES AT TRAFFIC STOPS

According to LASD West Hollywood Station data, once vehicles were stopped:

What does this show?

This visualization shows, out of the same number of stopped people, how many people 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 1,000 to get the per 1,000 stops rate.

Police are typically required to search people they arrest and vehicles they impound or tow. When the search reason is provided in the law enforcement agency’s data, these mandatory 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. Otherwise, this analysis includes any search that was not recorded as mandatory, including both discretionary searches and those with no search reason provided.

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

 

Data required for this analysis:

COMPARING SEARCH OUTCOMES AT TRAFFIC STOPS

One common explanation for racial disparities in stops and searches is that members of some racial groups may be more likely to have contraband. To assess this, this analysis examines how often officers recorded discovering contraband such as alcohol or stolen goods in searches of drivers in each racial group.

When discovery rates are lower for searches of people experiencing disparities, this may indicate that officers more frequently decide to search members of this group at a lower level of suspicion. When discovery rates are relatively similar across racial groups, it suggests that significant racial disparities in stop and search rates cannot be justified by differences in the outcomes of those searches. It’s also important to note that the discovery of contraband at traffic stops is generally rare and not indicative of a serious crime. For details on the types of contraband most often discovered, please see “More Information” below.

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 people 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. 

It is important to compare this chart to the percentage of traffic 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 people 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:

TRAFFIC STOP REASONS BY RACIAL GROUP

 

This analysis investigates which stop reasons are most often recorded for drivers of each racial group and overall.

Stops that are not based on any direct risks to road safety or evidence of criminal activity—such as equipment stops and license or registration checks—are less likely to be efficient uses of  departmental resources and more likely to contribute to racial disparities. Localities are increasingly seeking to eliminate these kinds of low-level stops because they unnecessarily subject drivers to harmful outcomes including fines and fees, searches, and use of force

 

What does this show?

Each of the above graphs show the racial distribution of stops recorded for a different stop reason. The colored bars within each graph show 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. Any stop reason that was recorded in a high number of stops, or that has large disparities, will influence the racial makeup of traffic stops overall.

The most common reason for contact with the police in the United States is being the driver in a traffic stop, and Black people are more likely to be stopped by police. Black people may also be more likely to be stopped for reasons that tend to be less related to public safety –such as equipment stops and license or registration checks– which unnecessarily increases their likelihood of being searched, experiencing police use of force, and being killed by police. Jurisdictions should invest in evidence-informed practices that reduce the footprint of policing on traffic safety to address persistent racial disparities in traffic enforcement that pose an ongoing public safety risk to Black people.

How was this calculated?

We took the total recorded stops of people 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:

TRAFFIC STOP OUTCOMES BY RACIAL GROUP

This analysis investigates which stop outcomes are most often recorded for drivers of each racial group and overall. According to LASD West Hollywood Station data, once vehicles were stopped:

Drivers who are more likely to be stopped despite not posing any clear risk to public safety are unnecessarily exposed to a greater risk of harmful stop outcomes including searches, arrests, and use of force. Reducing these kinds of low-level stops can help reduce racial disparities in policing and free up departmental resources for appropriate public safety needs. 

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.

Findings on recorded traffic stop outcomes should be interpreted in context with findings on racial disparities in recorded stop reasons and searches at traffic stops. People of racial groups who are stopped more frequently are often also more likely to be stopped for reasons that tend to be less related to public safety, which may increase their likelihood of being released with a warning or no action taken, as well as decrease their likelihood of receiving a citation. People who are more likely to be stopped despite not committing any crime or infraction are subject to a greater burden of police contact, which increases the likelihood of a cascade of interrelated harms including arrest, criminalization, and even injury or death.

How was this calculated?

We took the total recorded stops of people 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 outcomes 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:

TRAFFIC STOPS BY WORK UNIT AND RACIAL GROUP

Traffic Stop Totals by Work Unit, Separated by Racial Group

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Data on deputy work units were provided by the LASD West Hollywood Station. However, data were not collected with enough detail to identify deputies’ work unit assignments at the time each stop in the dataset was recorded. For details on data required for this analysis, see “More information” below.

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. 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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