VEHICLE STOPS

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

VEHICLE STOPS BY RACIAL GROUP

According to Los Angeles County Sheriff’s Department Carson Station data on vehicle stops recorded between 20XX and 20XX:

Unlike CPE’s analyses of use of force incidents and pedestrian stops, this analysis does not directly compare vehicle stops to local demographics because the driving population is more likely to include commuters and other non-residents whose racial makeup may differ from local Census data. However, if the racial makeup of people stopped while driving differs significantly from that of the resident population, it may indicate that there are racial disparities in vehicle 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 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:

VEHICLE STOPS BY YEAR

The total number of vehicle stops recorded each year with complete data varied from a high of XX in 20XX to a low of XX in 20XX.

What does this show?

This chart shows the number of vehicle stops recorded during each year of the assessment period for all racial groups combined.

Disruptions related to the COVID 19 pandemic may have affected the volume of police-community interactions recorded in 2020 and 2021, although the extent of this impact likely varies by jurisdiction according to the local policies and restrictions implemented in response to the outbreak. It is worth noting whether or the extent to which racial disparities persisted over this time period, despite the reduction in overall police activity.

How was this calculated?

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. 

Data required for this analysis:

COMPARING SEARCH RATES AT VEHICLE STOPS

According to Los Angeles County Sheriff’s Department Carson Station data, once vehicles were stopped:

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 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 VEHICLE 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 drivers 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 people 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 lead to high totals of contraband found. It’s also important to note that discovered contraband is not necessarily indicative of serious crime. It’s rare that contraband of any kind is found during a search, and an even smaller fraction of discovered contraband is related to serious criminal activity. Many instances of discovered contraband are simple drug possession, gun registration issues, or open containers of alcohol. While more substantial discoveries do occur, they come at the expense of thousands of stops that yield nothing; contraband searches are fundamentally unproductive and do not prevent serious crime. As such, police are considering more cost-effective strategies to prevent and respond to impaired driving, as well as address other issues like gun violence that more directly implicate public safety.

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 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:

VEHICLE 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 vehicle 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 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

This analysis investigates which stop outcomes are most often recorded for drivers of each racial group and overall. According to Los Angeles County Sheriff’s Department Carson Station data:

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 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 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:

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