The Supreme Court made profiling harder to challenge in Whren v. United States in 1996. It ruled that a traffic stop is legal if an officer saw any violation, whatever the officer's real motive. That allows pretextual stops, where a minor violation like a broken taillight becomes a reason to stop and search a driver.
The data shows the pattern. The Stanford Open Policing Project analyzed nearly 100 million traffic stops and found that Black drivers were stopped more often than white drivers. The gap narrowed after dark, when officers could less easily see a driver's race. In New York City, police made about 685,000 stops in 2011 under stop-and-frisk, most of them of Black and Latino people. A federal judge ruled the program's use unconstitutional in Floyd v. City of New York in 2013.
Profiling extends beyond police. After the September 11, 2001 attacks, Muslim, Arab and South Asian people faced heightened screening and surveillance. Stops carry risk: a routine stop can escalate into arrest, force or death.