The Fifth and Fourteenth Amendments prohibit law enforcement officers from engaging in discriminatory behavior on the basis of individuals’ race, ethnicity, or national origin. The Fifth Amendment protects against discrimination by federal law enforcement officers, and the Equal Protection Clause of the Fourteenth Amendment protects against discrimination by state and local law enforcement officers. Two federal statutes also prohibit discrimination by law enforcement agencies that receive federal financial assistance. Title VI of the Civil Rights Act of 1964prohibits discrimination on the basis of race, color, or national origin by all recipients of federal financial assistance. The Omnibus Crime Control and Safe Streets Act of 1968 prohibits discrimination on the basis of race, color, national origin, sex, or religion by law enforcement agencies that receive federal funds pursuant to that statute. In addition, a 1994 statute grants the Attorney General the authority to seek injunctive relief when a state or local law enforcement agency engages in a pattern or practice of conduct that violates the Constitution or federal law, regardless of whether the agency is a recipient of financial assistance. The Fourth Amendment guarantees the rights of people to be secure from unreasonable searches and seizures. The temporary detention of individuals during the stop of an automobile by police constitutes a seizure of persons within the meaning of the Fourth Amendment. The Supreme Court recently held that regardless of an officer’s actual motivation, a stop of an automobile is reasonable and permitted by the Fourth Amendment when the officer has probable cause to believe that a traffic violation occurred. The Court noted, however, that the Constitution prohibits selective enforcement of the law based on considerations such as race, but the constitutional basis for objecting to intentionally discriminatory application of laws is the equal protection provisions of the Constitution, not the Fourth Amendment. Some have expressed concern that the escalation of this country’s war on drugs has placed minorities at increased risk of discriminatory treatment by law enforcement. The allegation is that law enforcement officers stop minority motorists for minor traffic violations when, in reality, the stop is a pretext to search for drugs or other contraband in the vehicle. In 1986, the Drug Enforcement Administration (DEA) established Operation Pipeline, a highway drug interdiction program that trains federal, state, and local law enforcement personnel on indicators that officers should look for that would suggest possible drug trafficking activity among motorists. In a 1999 report, the American Civil Liberties Union (ACLU) stated that Operation Pipeline fostered the use of a racially biased drug courier profile, in part by using training materials that implicitly encouraged the targeting of minority motorists. DEA’s position is that it did not and does not teach or advocate using race as a factor in traffic stops. Further, according to DEA officials, a 1997 review of Operation Pipeline by the Justice Department’s Civil Rights Division, which is responsible for the enforcement of statutory provisions against discrimination, concluded that Operation Pipeline did not instruct trainees to use race as a factor in traffic stops. Representatives of organizations representing law enforcement officers have stated that racial profiling is unacceptable. The National Association of Police Organizations, representing more than 220,000 officers nationwide, has expressed opposition to pulling over an automobile, searching personal property, or detaining an individual solely on the basis of the individual’s race, ethnicity, gender, or age. The International Association of Chiefs of Police, one of the largest organizations representing police executives, stated that stopping and searching an individual simply because of race, gender, or economic level is unlawful and unconstitutional and should not be tolerated in any police organization. Neither group supports federally mandated collection of data on motorist stops. Lawsuits alleging racial profiling have been filed in a number of states, including Oklahoma, New Jersey, Maryland, Illinois, Florida, Pennsylvania, and Colorado. For example, in Colorado, a class action suit filed on behalf of 400 individuals asked the court to halt racially based stops by a Sheriff’s Department highway drug interdiction unit. Traffic infractions were cited as the reason for stopping the motorists, but tickets were not issued. The court ruled that investigatory stops based solely on motorists’ match with specified drug courier indicators violated the Fourth Amendment’s prohibitions against unreasonable seizures. A settlement was reached that awarded damages to the plaintiffs and disbanded the drug unit. In another case, a class action lawsuit filed by ACLU against the Maryland State Police resulted in a settlement that included a requirement that the state maintain computer records of motorist searches. These records are intended to enable the state to monitor for any patterns of discrimination.In yet another case, a Superior Court in New Jersey ruled that the New Jersey State Police engaged in discriminatory enforcement of the traffic laws. The Justice Department’s Civil Rights Division has recently completed investigations in New Jersey and Montgomery County, MD, which included reviewing complaints of discriminatory treatment of motorists. In the New Jersey case, Justice filed suit in U.S. District Court alleging that a pattern or practice of discriminatory law enforcement had occurred. The parties filed a joint application for entry of a consent decree, which the judge approved in December 1999. Under the consent decree, state troopers in New Jersey will be required to collect data on motorist stops and searches, including the race, ethnicity, and gender of motor vehicle drivers. In the Maryland case, the Justice Department and Montgomery County signed a Memorandum of Understanding in January 2000 that resolved the issues raised in Justice’s investigation. The agreement included the requirement that the Montgomery County Police Department document all traffic stops, including information on the race, ethnicity, and gender of drivers. Lack of empirical information on the existence and prevalence of racial profiling has led to calls for local law enforcement to collect data on which motorists are stopped, and why. To support local data collection efforts, the Bureau of Justice Assistance plans to release a Resource Guide in spring of 2000. The guide is expected to focus on how data can be collected to monitor for bias in traffic stops, with specific “lessons learned” and implementation guidance from communities that have begun the data collection process. Our objectives were to provide information on (1) analyses that have been conducted on racial profiling of motorists by law enforcement; and (2) federal, state, and local data currently available, or expected to be available soon, on motorist stops. To obtain information on analyses that have been conducted on racial profiling of motorists, we did a search of on-line databases and reviewed all of the quantitative analyses that we identified that attempted to address whether law enforcement officers stop motorists on the basis of race. We also contacted the authors of the analyses and obtained references to any other analysis or research sources they considered to be pertinent. Our criterion for selecting analyses to be included in this report was that they provide quantitative information on motorist stops, although these analyses might have also measured searches, arrests, and/or other activities. We used social science research principles to assess the methodological adequacy of the available analyses and to discuss factors that should be considered in collecting stronger empirical data. Our review is not intended to constitute a statement regarding the legal standard for proving discrimination in this context. To obtain information on the federal government’s efforts to collect data on racial profiling of motorists, we reviewed published and electronic literature and discussed data sources with officials at the Justice Department’s Bureau of Justice Statistics (BJS), officials in the office of the Attorney General, academic experts, the American Civil Liberties Union (ACLU), and several police associations. To obtain information on states’ efforts to collect data on racial profiling of motorists, we conducted Internet searches and reviewed the literature. We also held discussions with academic experts, state officials, ACLU officials, and representatives of the National Conference of State Legislatures. To obtain information on local efforts to collect data on racial profiling of motorists, we reviewed the literature and held discussions with academic experts, interest groups, local police officials, and knowledgeable federal officials. On the basis of these discussions, we judgmentally selected several communities that had voluntarily decided to require their police departments to collect motorist stop data. In September 1999, we visited four police departments in California—in San Diego, San Jose, Alameda, and Piedmont. We selected these police departments because they appeared to be furthest along in their plans for collecting data, could provide examples of different data collection methods, and varied greatly in size. We performed this work from August through February 2000 in accordance with generally accepted government auditing standards. We found no comprehensive, nationwide source of information on motorist stops to support an analysis of whether race has been a key factor in law enforcement agencies’ traffic stop practices. We identified five quantitative analyses on racial profiling that included data on motorist stops. The quantity and quality of information that these analyses provided varied, and the findings are inconclusive for determining whether racial profiling occurred. Although inconclusive, the cumulative results of the analyses indicate that in relation to the populations to which they were compared, African Americans in particular, and minorities in general, may have been more likely to be stopped on the roadways studied. A key limitation of the available analyses is that they did not fully examine whether the rates and/or severity of traffic violations committed by different groups may have put them at different levels of risk for being stopped. Such data would help determine whether minority motorists are stopped at the same level that they commit traffic law violations that are likely to prompt stops. Most analyses either compared the proportion of minorities among stopped motorists to their proportion in a different population (e.g., the U.S. population, the driving age population of a state) or did not use a benchmark comparison at all. There appears to be little comparative research on traffic violations committed by different racial groups, including possible differences in the type or seriousness of traffic violations. Therefore, there are no firm data indicating either that the types and seriousness of driving violations committed by whites and minorities are comparable, nor that they are not.