Recommendation area ▸

Addressing Racial Disparities in Traffic Stops

The Problem ▸

Although traffic stops have been shown to improve traffic safety and reduce and prevent crime, they have also been associated with harmful police-community interactions. Black motorists are disproportionately stopped by the police, more likely to be searched, cited, and arrested, and are less likely to be treated with respect during the stop.[1] This has been associated with psychological harm and damage to trust in the police.[2] The risk of harm may be enhanced when the volume of stops, or stop-related outcomes, are linked to officer performance through formal or informal “quotas.” Pretextual or investigative stops, in particular, can lead to decreased perceptions of police legitimacy and increased safety risks to both the public and the officers. Given the potential harms caused by traffic enforcement, their use must be carefully tied to traffic safety, closely monitored by agency supervisors and leadership, and carried out by officers trained in procedural justice.

What We Know ▸

Traffic stops are common and most are carried out respectfully

Nearly 15% of all police-community contacts in the United States were traffic-related in 2018 (more than 18.6 million traffic stops). Traffic stops are the most common reason for public contact with the police.[3] A discretionary tool, they are the most common form of proactive policing. Given the high level of discretion and limited oversight, traffic stops are at risk of both implicit and explicit bias. Nevertheless, more than 85% of people involved in a traffic stop reported that officers behaved properly and treated them with respect. Black drivers were less likely to report the reasons for the stop as legitimate compared to Hispanic/Latino and White drivers.[4]

Roadways are more dangerous for people of color

Blacks had the second highest per capita rate (68.5 per 100,000) of total traffic deaths nationally (2001–2010), exceeding the per capita rate of White traffic deaths (55.2 per 100,000).[5] This was true for total traffic deaths, pedestrian traffic deaths, and bicyclist traffic deaths. People who live in areas of great economic hardship have an increased risk of being in a severe crash and dying in a traffic crash more often and at a higher rate than residents of more affluent neighborhoods.[6]

Traffic stops can effectively reduce crime and improve roadway safety

Traffic stops are used for two primary uses to improve traffic safety and to prevent and/or investigate crime (pretextual stops). The U.S. Supreme Court, in Whren v. United States, determined that pretextual stops are constitutional.[7] Research has demonstrated that traffic stops can effectively reduce traffic injuries and fatalities, and violent crime, particularly homicides, shootings, and illegal gun possession. To be effective, traffic stops must be highly focused on particular driving behaviors and locations; however, research indicates that the location of stops does not always align well with areas of traffic safety risk. Appropriating officers from traffic duties for other purposes, such as revenue collection[8] and measures or displays of police productivity, has negative repercussions and unnecessarily puts officers and the community at risk.

Traffic stops can be dangerous, but most of the danger comes from traffic-related fatalities

Traffic stops pose dangers for both officers and the individuals stopped, even though officers do not use force in most traffic stops.[9] This suggests that eliminating traffic stops will not likely result in major reductions in officer-involved shootings. In contrast, officer injuries from traffic collisions are much more common. Traffic-related fatalities, including being struck by a vehicle while working along a roadway, are among the most common cause of officer fatalities.[10] Data from 2021 found a substantial increase in “struck-by” incidents where officers are struck by another vehicle while working on the road or roadside.[11]

There are alternatives to traditional traffic enforcement

Systematic reviews and meta-analyses found that speed cameras[12] can reduce fatal and non-fatal crashes, although they may not resolve all racial disparities. Red-light cameras (RLCs) may effectively reduce red light violations and are likely to reduce some types of traffic crashes.[13] More recently, automated traffic enforcement through network-connected vehicles has been proposed as a way to reduce the need for discretionary traffic enforcement.[14]

Assessing bias and disparity in traffic stop activity is challenging

Developing appropriate benchmarks for measuring racial disparities in traffic stops is challenging.[15] There are considerable limitations in using population data as a benchmark [16] [17], and scholars have argued that their use provides limited analytic value or is misleading.[18] Compounding this problem, the relative value of the population as a benchmark appears to vary by place and type of agency (e.g., state highway patrol versus municipal police).[19] At the operational level, law enforcement agencies face additional challenges in tracking and assessing for bias and disparity. Many approaches require sophisticated statistical modeling, skills which may not exist in agencies. Smaller agencies may also be limited by the small volume of traffic stops, making many analytic techniques unfeasible. Finally, most assessment approaches take an aggregate approach to assessing bias and disparity, and few approaches have been tested for officer- or command-level performance.

Council Recommendations ▸

Recommendation 1

Reduce Reliance on Traffic Stops

Traffic stops, while not always improving driver and pedestrian safety, must be reduced to decrease the criminalization of community members and racial and economic disparities. Alternative traffic-safety strategies focusing on high-risk behaviors, including automated tools and civilian-led traffic-safety enforcement. Alternative strategies should be rigorously evaluated to determine their effectiveness in reducing disparate impact and negative police-community encounters while maintaining roadway and pedestrian safety.

Recommendation 2

Abolish Performance Incentives and ‘Quotas’ Based on the Volume of Traffic Stops

Agencies must stop the use of traffic stop volume as a performance measure. Agencies should instead rely on problem-solving approaches that use stops when and where data suggests that traffic-safety issues (collisions, complaints) or crime may be prevalent.

Recommendation 3

Change Laws and Policies Regarding the Use of Pretextual (Investigative) Stops

Policies and laws that encourage or allow pretextual stops for minor safety violations, such as items hanging from mirrors, lights out, and other minor mechanical issues, should be changed.

Recommendation 4

Explore and Evaluate Alternatives to Traditional Traffic Enforcement and Roadway Safety Approaches

Alternative approaches to enforce traffic laws and improve roadway safety should be explored, including civilian-based organizations to enforce minor traffic and vehicle violations and respond to non-injury traffic collisions. Alternative strategies should be rigorously and independently evaluated for their impact on outcomes, including public safety and racially disparate impacts.

Recommendation 5

Implement Diverse Approaches to Reduce Traffic Injuries and Fatalities

Implement a variety of evidence-based strategies to reduce traffic-related injuries and fatalities, particularly where they disproportionately occur among groups and within communities. Proposed frameworks include the Data-Driven Approaches to Crime and Traffic Safety (DDACTS) model, education campaigns, and roadway modification.

Recommendation 6

Officers Should Receive Training on Using Procedural Justice Principles in Traffic Stops and Require Signed Consent for Vehicle Searches

To reduce negative interactions and potentially coercive situations, officers should receive training on using principles of procedural justice in traffic stops. Training should include skills in active listening, neutral and transparent decision-making, and demonstrating dignity and respect toward community members. Signed consent forms should be required prior to voluntary vehicle searches.

Recommendation 7

Monitor Traffic Stop Activity for Bias and Disparate Impact

Regular monitoring of traffic stop activity will ensure there is no bias or racially disparate impact and outcomes. This analysis should be conducted at both officer- and organizational-levels (e.g., by special assignment, districts) and be broader than basic stop data, including officer behavior captured via body-worn cameras.

Recommendation 8

Collect and Disseminate Traffic Stop Data at the Agency and State Levels and Disseminate to the Public

Detailed data on officer traffic stops should be collected at the agency and state levels and submitted to a centralized state repository. These data should include the time, date, and precise location of the stop, the reason for the stop, and the outcomes, including searches and searches incidental to arrest, contraband recovery, arrests and charges, and the demographic details of those involved. States should promote accountability and transparency by releasing such data to the public.

Recommendation 9

Use Traffic Stop Data to Improve Early Intervention Systems

A more detailed and identifiable dataset (see Recommendation 8 above) should be used to develop anti-bias, early intervention, and early-warning systems. Stop data for every officer should be reviewed to detect potential bias and to intervene to mitigate bias. Agency-wide aggregate data and the actions taken should be monitored to reduce disparate outcomes.

Dissenting Views ▸

Traffic stops are an important law enforcement and investigative tool that has proven to protect communities and enhance roadway and pedestrian safety. Proactive traffic enforcement reduces crash rates and ensures that vehicles on the road are in compliance with safety regulations. I do not believe the intent of the council is to simply reduce traffic enforcement. As a former police chief, who also served as commander of the traffic enforcement and traffic homicide units, I vehemently disagree with encouraging any law enforcement agency to simply reduce traffic enforcement. However, I do believe the ultimate intent of the council is to reduce racial profiling and other inappropriate behavior that violates department policies and, in some cases, violates the law.

As we wrestle with our criminal justice system and debate the best, most effective ways to improve it, we must always remember that public safety is and must continue to be our top priority. Police executives must continue to emphasize unbiased policing, provide human diversity training, ensure departments reflect the diversity of the communities they serve, acknowledge good performance, and hold bad actors accountable.

In effort to ensure these stops are not leveraged negatively against certain communities, officers should report the nature of the stop and whom they pulled over. Such reports should be given to the law enforcement department for auditing purposes to ensure communities of color are not being negatively impacted. Violations in biased policing should be heavily punished.

Council Co-Chair, Congresswoman Val Demings

Further Research ▸

Research is needed to determine if implicit bias training effectively reduces racial disparities in traffic enforcement.

Agencies are implementing implicit-bias training to reduce racially disparate outcomes. However, few evaluations demonstrate the effectiveness of this training, especially as it relates to racial disparities in traffic stops.

More research is needed to develop procedural justice training content that generalizes to a wide range of law enforcement agencies and communities. Current procedural justice training is often lengthy and can present considerable barriers to implementation. Research exploring a variety of training lengths and formats is needed.

Conduct exploratory research to better identify the costs and benefits of reducing traffic enforcement by law enforcement, including what, if any, impact prohibiting or deprioritizing traffic stops for minor equipment violations may have on racial-disparate outcomes and on traffic safety and crime.

Develop research exploring methods that law enforcement agencies can use to reduce the use of traffic stops as a performance measure. Existing performance measures typically focus on policing outputs (e.g., the number of traffic stops or citations issued) because they are easy to measure using administrative data. Alternatives that better measure successful policing need to be developed and tested.

Traffic stops can be effective in reducing crime, but less is known about how they can also reduce racial disparities. Research should be conducted to explore how traffic stops can equitably be used while maintaining and supporting public safety.

Implement and evaluate alternatives to traditional traffic enforcement strategies. Despite the absence of evidence, civilian traffic safety is being explored by a variety of jurisdictions. Research is needed to understand the effectiveness and safety of this approach. Alternative approaches to roadway safety, such as adapting road design, should also be studied.

Support the development of more robust benchmarks for assessing disparities and bias. Typical approaches that rely on census demographic data are extremely limited. Examples of alternatives could include observational studies and analysis of other traffic data, such as traffic camera or collision data.

Citations ▸

[1] Voigt, R., Camp, N. P., Prabhakaran, V., Hamilton, W. L., Hetey, R. C., Griffiths, C. M., Jurgens, D., Jurafsky, D., & Eberhardt, J. L. (2017). Language from police body camera footage shows racial disparities in officer respect. Psychological and Cognitive Sciences, 114(25). https://doi.org/10.1073/pnas.1702413114

[2] Epp, C.R., Maynard-Moody, S. and Haider-Markel, D. (2017), Beyond Profiling: The Institutional Sources of Racial Disparities in Policing. Public Admin Rev, 77: 168-178. https://doi.org/10.1111/puar.12702

[3] Harrell, E., & Davis, E. (2020). Contacts between Police and the Public, 2018 – Statistical Tables. Bureau of Justice Statistics. https://bjs.ojp.gov/library/publications/contacts-between-police-and-public-2018-statistical-tables

[4] Langton, L, and Durose, M. (2013). Police Behavior during Traffic and Street Stops, 2011. Bureau of Justice Statistics.

[5] Governors Highway Safety Association. (2021). An Analysis of Traffic Fatalities by Race and Ethnicity. https://www.ghsa.org/sites/default/files/2021-06/An%20Analysis%20of%20Traffic%20Fatalities%20by%20Race%20and%20Ethnicity.pdf

[6] Naumann, R.B., & Beck, L.F. (2013). Motor vehicle traffic-related pedestrian deaths — United States, 2001–2010. Morbidity and Mortality Weekly Report, 62(15), 277-282.

[7] Whren v. United States, 517 U.S. 806 (1996). https://supreme.justia.com/cases/federal/us/517/806/

[8] Piven, B. (2021, February 2). When Police Become Tax Collectors. Q&A, Arnold Ventures. https://www.arnoldventures.org/stories/when-police-become-tax-collectors/

[9] Stephens, D. (2019). Officer-involved shootings: Incident executive summary. National Policing Institute.

[10] Center for Disease Control and Prevention. (n.d.). Law enforcement officer motor vehicle safety. See https://www.cdc.gov/niosh/topics/leo/default.html

[11] National Law Enforcement Memorial and Museum. (2022). 2021 End-of-year preliminary law enforcement officers fatalities report.

[12] Center for Disease Control and Prevention. (n.d.). Automated Speed-Camera Enforcement [Fact sheet]. https://www.cdc.gov/motorvehiclesafety/calculator/factsheet/speed.html

[13] Center for Disease Control and Prevention. (n.d.). Automated Red-Light Enforcement [Fact sheet]. https://www.cdc.gov/motorvehiclesafety/calculator/factsheet/redlight.html

[14] Joh, Elizabeth. (2006). Discretionless Policing: Technology and the Fourth Amendment. California Law Rev.. 95.

[15] See, for example, Grogger, J., & Ridgeway, G. (2006). Testing for Racial Profiling in Traffic Stops From Behind a Veil of Darkness. Journal of the American Statistical Association, 101(475), 878-887. https://www.rand.org/content/dam/rand/pubs/reprints/2007/RAND_RP1253.pdf

[16] Alpert, G., Smith, M., & Dunham, R. (2004). Toward a Better Benchmark: Assessing the Utility of Not-at-Fault Traffic Crash Data in Racial Profiling Research. Justice Research & Policy, Spring, 43.

[17] Smith, W., Tomaskovic-Devey, D., Zingraff, M., Mason, M.H., Warren, P., Wright, C. P., McMurray, H., & Fenlon, C. R., The North Carolina Highway Traffic Study 6 (U.S. Department of Justice, Working Paper No. 204021, 2004)

[18] Withrow, B., & Williams, H. (2015). Proposing a Benchmark Based on Vehicle Collision Data in Racial Profiling Research. Criminal Justice Review. 40. 449.

[19] Lovrich, N. P., Gaffney, M. J., Mosher, C. M., Pickerill, M., Pratt, T. C. (2005). Analysis of traffic stop data collected by the Washington State Patrol: Assessment of racial and ethnic equity and bias in stops, citations, and searches using multivariate quantitative and multi-method qualitative research techniques. University of Washington, Submitted to the Washington State Police, Olympia, WA.