Earlier this year, the San Francisco Police Commission passed a policy prohibiting officers from making traffic stops for nine types of traffic infractions, described in Table 1 below.

The policy bans police officers from conducting certain kinds of pretext stops, a tactic in which an officer pulls over a driver for a minor traffic violation with the goal of investigating more serious criminal activity. These stops present an equity issue, as they are often used to disproportionately question and search Black and Latino drivers.

Along with banning stops for certain infractions, the policy also limits the kinds of questions that police can ask after any traffic stop, a component that should have a noticeable impact, says San Francisco Police Commissioner Max Carter-Oberstone, who introduced the initial policy proposal.

“The second piece of the policy tries to remove the incentive for making a pretext stop”—the incentive being the ability to investigate whether a driver has committed a more serious crime, he asserts.

What inspired San Francisco to pursue this policy now?

Since the murder of George Floyd in 2020, communities across the country have debated how to reduce or eliminate racial bias and excessive violence faced by people of color in policing encounters. These debates have led to several types of attempted reform strategies.

More recently, several cities—including San Francisco—adopted reforms to their pretext stop policies with the aim of transforming how police interact with drivers.

Not everyone agrees with these reforms. Pretext stop policy reforms have been seen by some as controversial, and receive varying amounts of support within communities and pushback from police.

What is the source of this controversy? Why have so many police departments adopted these reforms? Can we reduce disproportionate harm to Black and Latino drivers that occurs after minor traffic stops by reducing the frequency of these stops?

How do pretext stops work?

To begin to answer these questions and to understand why pretext stops are championed as well as criticized, let’s illustrate how they work.

Imagine, two District of Columbia Metropolitan Police Department officers in an unmarked car, patrolling what they believe to be a high drug area in the nation’s capital. They spot an SUV waiting at a stop sign for what they later describe as an unusually long time, and then observe the car turn at an “unreasonable” speed and without signaling. The officers decide to stop the vehicle, later saying they wanted to warn the driver of traffic violations; and when they approach the car, they say they see bags of crack cocaine in the passenger’s hands while looking through the driver’s window. The officers search the vehicle, find several types of drugs, and arrest both the passenger and driver who are ultimately indicted on federal drug charges, including possession with the intent to distribute.

These were the circumstances in the important 1996 Supreme Court case Whren v. United States.

The drivers, Michael Whren and James Brown, argued that the discovery of the drugs should be kept out of their criminal case, as the officers had no reasonable suspicion, let alone probable cause, to believe that Whren or Brown were involved in drug dealing. Because the stop for traffic code infractions seemingly was used as a “pretext” to investigate drug dealing, they argued, the evidence should be inadmissible and was obtained in violation of the Fourth Amendment’s protection against unreasonable searches and seizures.

But the Court disagreed, ruling in favor of the police and the government.

The Court explained that so long as a police officer has reasonable cause to believe that a motorist committed a traffic violation, they may stop a vehicle, even if the officer would not have stopped the vehicle if they did not have an “additional law enforcement objective.”

What were the implications of this decision? As policing scholar David Harris put it, the Supreme Court decision essentially gave police officers the unlimited power to detain greater numbers of Black and Latino drivers.

He explained that the expansive scope of traffic laws combined with racially biased policing meant that the case represented “a clear step…toward authoritarianism, toward racist policing, and toward a view of minorities as criminals, rather than citizens.”

And in the nearly 30 years since this case, we can see how Harris’ prediction rings true.

Our colleagues at the Stanford Open Policing Project have shown how, across the country, Black drivers are more likely to be pulled over than white drivers. In a 2020 study, they found that racial disparities in traffic stops decrease at night when officers are less likely to be able to discern the race of the driver. Here in California, Black and Latino drivers are also more likely to be searched when stopped.

This unequal form of policing is especially harmful when we consider the fact that traffic stops make up the most common form of police-civilian interaction.

That’s why in 2021, our Center developed a report with the Stanford Criminal Justice Center to call for cities to end or heavily restrict the practice, a recommendation echoed nationally by legislators and advocates.

Because Black and Latino Americans interact with police more often, they experience the impact of police traffic enforcement more intensely. A 2006 study showed that African American and Latino male drivers were more likely to report that the police behaved improperly and seemed to have an illegitimate reason to stop them than white male drivers. There is also a negative psychological impact caused by increased traffic surveillance and policing of Black communities.

With this evidence against pretext stops, why have police continued to utilize them?

Police officers argue that pretext stops allow police to better do their jobs; with this tool, police can reduce injury and death, catch criminals, and regularly confiscate contraband like drugs and weapons. Without pretext stops, our streets would be much less safe, officers argue.

However, a growing body of research contradicts this justification. An analysis of North Carolina traffic stops from 2002 to 2020 found that drugs were seized in only 0.53 percent of all traffic stops, while weapons were seized in only 0.11 percent. In California, firearms were confiscated in only 905 traffic stops out of the 3.4 million made in 2019. And these stops are costly to society, both in terms of punitively expensive citations for drivers and the use of taxpayer-funded police that could be addressing other public safety needs.

Following mass protests in 2020, police departments around the country were forced to justify several of their policing practices, including pretext stops. And, in a sharp reversal of the decades-long trend to expand police investigatory authority, many jurisdictions started banning or limiting low-level traffic violations, stripping police of a once-valued law enforcement tool. San Francisco’s attempt to rein in pretext stops offers an important window into the promise and challenges of these policy reforms.

Pretext Stop Reform in San Francisco

Often called one of the most liberal cities in the U.S., San Francisco’s attempts to pass this policy led to a lengthy, complicated fight.

The reform policy was first introduced to the public in May 2022. In the original version, the Police Commission sought to limit 18 types of traffic stops. However, months later, the Police Commission pared down the list to nine types of stops and tabled a vote on the decision.

Table 1: Banned Traffic Stops, pursuant to San Francisco Police Department General Order 9.07

1.      Failure to display or properly mount license plates when the rear plate is still visible and legible

2.     Failure to display registration tags or driving with an expired registration of more than one year

3.     Failure to illuminate rear license plate

4.     Driving without functioning or illuminated rear taillights

5.     Driving without functioning or illuminated rear brake lights

6.     Driving with objects affixed to windows or hanging from rearview mirror, unless it creates a condition that substantially increases the likelihood of a crash

7.     Failure to activate a turn signal continuously for 100 feet before turning

8.     Sleeping in a vehicle

9.     Any stop of a pedestrian for an infraction in violation of the California Vehicle Code or San Francisco Transportation Code, unless there is an immediate danger the pedestrian will crash

For many, a question lingered; what led to this change?

Two factors influenced the revision. First, the Police Commission received new data.

Essentially, when drafting the original list of 18, the Police Commission wanted to ensure that the infractions that were deprioritized had no impact on public safety. And initial data supported the fact that enforcing these 18 infractions did not actually lead to safer streets. However, Carter-Oberstone tells us that further data found that some of these infractions were leading to some crashes, stops where contraband was discovered, and arrests. Others were not leading to stops at all.

For the Police Commission, it was important to have a list that both officers could easily commit to memory and still have the impact they wanted to see.

Another important point to emphasize: The idea that the pretext stop policy was edited to respond to San Francisco’s particular public safety challenges. Pretext stop reforms have sprouted up all around the country, but the policies that stand to have the most impact are the ones that are tailored to the safety, policing, and racial justice issues facing their communities.

Last year, Los Angeles adopted its own pretext policy reform. LAPD officers have been instructed to only make stops that significantly impact public safety, a policy which excludes most non-moving violations and has been seen as a “middle ground” approach. Additionally, officers can only escalate an investigation during a traffic stop if they have observed suspicious behavior related to another crime occurring during the stop.

The result? LAPD officers stopped far fewer drivers and were also more likely to find contraband. During these stops, officers were also less likely to request and obtain a driver’s consent to search the car—a tactic known as a “consent search” and used by police when they cannot otherwise legally initiate a search.

On the East Coast, cities like Fayetteville, North Carolina have pursued significant pretext stop reforms. Between 2013 and 2016, Fayetteville Police Chief Harold Medlock told his officers to prioritize four types of traffic safety stops; speeding, stop sign/light violations, DWIs, and reckless driving.

The result was a decrease in vehicle searches from traffic stops, especially for Black drivers. According to Medlock, complaints against officers also went down. A 2020 analysis found that safety stops rose while traffic fatalities decreased.

Back in San Francisco, after receiving feedback and concerns through public dialogues, surveys, and closed door police officer-only sessions, the Police Commission took this input and used it to influence the pretext stop policy.

Much of the pushback against the policy was rooted in a victim-centered framework; that with this policy in place, police would be inhibited from catching law-breaking motorists and thus, less able to serve potential victims of traffic crimes. San Francisco, like many other major cities around the country, has been seized by “tough-on-crime” rhetoric, a major factor in former District Attorney Chesa Boudin’s notable defeat in a 2022 recall election.

In response to criticism that the policy will harm public safety, Carter-Oberstone says that this fear is not based in reality. “What we know for sure is that pretext stops are one of the most inefficient and ineffective ways to stop and prevent crime” he says, citing their low yield rates for contraband and arrests. To support this claim, he pointed to independent research and the San Francisco-specific data that shaped the city’s policy.

However, while the reform opposition was unsuccessful in its attempts to prevent this policy from being approved, its legislative and lobbying efforts may stand in the way of further police reform, both in San Francisco and beyond.

What’s Next for San Francisco and Pretext Reform Efforts

Although San Francisco’s policy has the Police Commission’s approval, it still has a long way to go before taking effect. The San Francisco Police Officers Association, the city’s largest police union, now has the opportunity to negotiate with the city about whether the policy affects its collective bargaining agreement. After the negotiations conclude, the Commission will then vote again on the agreement; if the policy is approved, the police department will likely have 30 to 60 days to train officers before the policy goes into effect. This whole process will be occurring during the same time California Senate Bill 50, aimed at ending pretext stops statewide, is being debated in Sacramento.

The impact of San Francisco’s reforms will only be fully understood once they have been implemented. But, already, the journey to get to this point raises interesting questions.

While communities that pressured police departments to change their practices have welcomed pretext stop reform policies as a partial step in a larger discussion, are these important, but modest reforms being touted by law enforcement meant to end the discussion entirely?

It is important to recognize the immense value of pretext stop reforms, both in harm mitigated for Black and Latinx communities but also money saved by putting police to better use protecting their communities. It is equally important to understand how these policies fit into a grand scheme of envisioning new, creative ways to promote public safety.

One of these ways involves taking the responsibility of traffic enforcement entirely out of the hands of police. How? We’ll tackle this question and more in our upcoming research on civilian led traffic enforcement.