When the coronavirus pandemic hit, California quickly realized that the 70,000 people jailed across the state would be especially vulnerable — and that an outbreak behind bars, once it began, could be uncontrollable. Many were incarcerated not because they’d been convicted of a crime, but simply because they couldn’t pay bail. Weighing the low risk many of these people posed to public safety against the high risk of viral spread, the state swiftly ended cash bail for misdemeanors and low-level felonies (including most fraud, vandalism and drug crimes). In just two months, the state reduced its jail population by 20,000 people, approximately one-third of the pre-pandemic total.

Countless jurisdictions have scrambled to mitigate these public health risks by changing their approach to criminal justice. Eliminating or reducing cash bail — a strategy also used in New Orleans and Tulsa — is one popular move. Several cities stopped arresting people for minor infractions, and in other places, prosecutors filed fewer charges. Officials undertook these efforts as temporary measures in response to a public health emergency, yet they reflect the types of sweeping changes that advocates of criminal justice reform have been promoting for years. They should be expanded and made permanent in communities across the country.

Criminal justice reforms inspired by the pandemic could, in short, spark long-lasting, fundamental change, making the system fairer and more just.

These efforts are decentralized, making them hard to keep track of. Our team at the Stanford Computational Policy Lab scoured local newspapers and talked to policymakers nationwide to find out what’s being done. The examples we unearthed touched every aspect of the criminal justice system, from policing to prosecution to prisons.

Issuing citations rather than arresting people is one common change. Police chiefs and sheriffs in Nashville, Chicago, Seattle and San Antonio took that tack for offenses such as public intoxication, drug use and petty theft. People who get citations may still face a court hearing and a fine, but they avoid often lengthy jail stays.

Arizona’s Maricopa County instructed its prosecutors to ease up on court filings to reduce the local jail population. Although police continued to send some 900 cases per week to the county attorney’s office during the pandemic, about the same number as in pre-coronavirus times, the rate of cases prosecuted dropped from 80 percent to just 12 percent by mid-April.

The probation system places an intense burden on the lives of many Americans. Mississippi and New York suspended the requirement that people on probation physically visit their probation officer. Instead, they could check in by phone, email or video. Enacted for public health reasons, this sensible change also makes it easier for people to juggle their job and child-care obligations with their probation requirements. Other changes that reduced health risks from outside visitors also made it easier for incarcerated people and their families to keep in touch. Colorado, for instance, is offering some free video visitation and phone call options. (Although, at one free 10-minute phone call a week, the change leaves much to be desired.)

Before and during the pandemic, our team has partnered with government agencies to reduce incarceration and discriminatory policing. In response to the coronavirus, for example, we worked (on a confidential basis) with a district attorney in a major U.S. county to design a platform that helps the office quickly review the cases of jailed individuals. The tool we built lets supervisors see why every person in the system is being held and what might be done to resolve their case — including immediate release. Coupled with other efforts by the county, this helped reduce the county’s jail population by nearly half.

Pandemic or not, no one should spend time in jail because a prosecutor has lost track of his or her case. Judges often sentence people to “time served,” so it makes a big difference if they have to wait two weeks or two months for their case to be resolved, and a system like the one we designed can help.

Unfortunately, there’s a good chance that many of these reforms will be rolled back after the immediate health risks have passed. California, for example, has already rescinded its statewide order limiting bail, leaving local courts to set their own policies — although a November referendum will give residents a chance to end money bail for good.

These rollbacks may be the result of fear that reducing arrests and prosecutions inevitably drives an increase in crime. Some people apparently believe that reducing arrests might be okay during a public health emergency — but only then. But the data, including data we have compiled, show that such reforms often have little if any negative effect on public safety.

Police reforms are typically preceded by alarmist warnings that crime will spike, but it rarely happens. In New York City, in the face of incontrovertible evidence that stop-and-frisk practices were discriminatory and ineffective (we did one analysis), the New York City Police Department reduced stops by more than 90 percent from 2011 to 2014 — from a high of nearly 700,000 stops per year to less than 50,000. Crime rates were constant throughout the period.

In 2012, the Metropolitan Nashville Police Department conducted almost 450,000 traffic stops, heavily concentrated among the city’s black residents. Many were for minor infractions, such as broken taillights, yet were justified as a strategy for combating serious crime, like burglary. (One former MNPD chief defended the policy by saying, bizarrely, “Crooks don’t ride horses, they drive cars.”)

After a local community group, Gideon’s Army, documented racial bias in these stops, we worked with the city to change the department’s practices. Our analysis found no connection between traffic stops and serious crime: The number of burglaries was the same in weeks with heavy enforcement as in weeks with few stops. Such data, in tandem with community pressure, prompted the city to scale back its tactics. Last year, the department stopped almost 90 percent fewer drivers than in 2012, with almost no change in crime rates.

Similar fears have also accompanied reductions in jail populations. When New Jersey ended money bail in 2016, opponents warned that crime would skyrocket. No such spike occurred, even as the state’s pretrial jail population shrank from approximately 9,000 to 5,000 people.

The pandemic has led policymakers to embrace reforms that many previously rejected as too radical. That gives reformers a crucial opening. Now that people see the changes in place, it’s easier to argue that they should stay.

The Black Lives Matter movement — and public outrage at the police killings of George Floyd, Breonna Taylor and other black men and women — has intensified demands to dismantle the criminal justice system. The pandemic has shown that policymakers can implement quick and dramatic changes when they choose to. We should make those changes permanent. We should also build on them to fundamentally reshape policing, prosecution and the justice system more broadly. The pandemic-inspired reforms are a good start — but still just a start.