Philly teens now have a 10 p.m. curfew for the summer. Here’s how it works.

Mayor Jim Kenney signed a bill Wednesday instituting an earlier curfew for Philadelphia teens this summer.

That means that beginning Thursday night, all kids age 17 and younger must be indoors and off the streets by 10 p.m.

The bill, introduced by City Councilmember Katherine Gilmore Richardson, passed unanimously and will be in effect through the end of September.

Supporters of the measure framed it as a final effort to keep young people safe this summer and potentially reduce juvenile crime rates amid the city’s ongoing gun violence crisis. Experts who study curfews, though, say the laws have no effect on crime or victimization rates.

» READ MORE: Philly teens are bracing for a new curfew — and assuming some will find a way around it

Here’s how the curfew works and what this new law means:

A curfew is a law, sometimes citywide other times state-mandated, that essentially makes it illegal for juveniles to be outside of their home after a certain time without a parent or guardian.

Through September, the city’s curfew has been set for all days of the week:

Young people and their parents could previously be fined for violating curfew, but Council suspended that last year.

Now, kids out past curfew can be stopped and picked up by police, who then must make “every reasonable attempt” to reach their parents or guardians and take them home.

If that’s not possible and depending on where they’re picked up, they’ll be taken to a Community Evening Resource Center, a Department of Human Services facility, or the police station.

It’s a new model that began in December, spearheaded by Gilmore Richardson, where kids who violate curfew and cannot be brought home are taken to a resource center instead of the police station.

The centers are open from 7 p.m. to 2 a.m., and provide a meal, comfortable place to rest, and programming — such as games, photography and carpentry classes, and conflict-resolution discussions. Young people of any age can stop into the centers voluntarily.

The centers are overseen by the Department of Human Services. More than 300 teens have been brought to the evening centers since the program began, the city said.

There are currently two in the city:

Two more are slated to open this summer in the Northwest and Central sections of the city, Gilmore Richardson said. If a police district does not have a resource center, officers will take the child to a DHS facility or the police station.

Philadelphia has had a curfew on the books since 1955, but it was updated in 2011 under Mayor Michael Nutter to become more stringent, then reviewed again by Council last year to eliminate citation fines and open resource centers.

City leaders have said curfews help keep kids out of harm’s way at night, when crime may be more prevalent, and also deter juvenile violence. At a time when Philadelphia’s escalating gun violence crisis has claimed the lives of numerous children, Gilmore Richardson said she’s “willing to try every tool in our toolbox” to keep kids safe and lower violence levels.

“If we do nothing, folks are mad. If we do something, folks are mad,” she said. “At the end of the day, we must do something to try to save the lives of our young people. We are losing a whole generation. We can’t accept that.”

Researchers of curfews call them “pointless,” and say they do little to curb crime or victimization rates.

“They feel good for officials to do, but they have no effect on crime, and possibly even a negative effect,” said Mike Males, senior researcher at the Center on Juvenile and Criminal Justice in San Francisco.

Males said it’s difficult for police to distinguish kids’ ages, and curfews can open the door for negative interactions between police and young people.

» READ MORE: Experts say Philly's 10 p.m. curfew is 'pointless'

A 2016 study from the Campbell Collective, which reviewed 12 studies on juvenile curfews, said the efforts were not a “meaningful solution” to juvenile crime, and found that crime during curfew hours increased slightly and juvenile victimization did not change. A 2017 study on Washington, D.C.’s juvenile curfew also found that shootings increased during the curfew hours, which researchers say could be because fewer bystanders and witnesses were on the streets to deter crime.

David B. Wilson, who headed the Campbell Collective study and is a professor at George Mason University’s Criminology, Law and Society Department, said most juvenile crime and victimization occurs outside of curfew hours. Plus, he said, it ineffectively uses police resources.

“People think about it as, well, what’s the harm if it helps a little bit?” he said. “But it’s actually a zero-sum game. If police are enforcing curfews, they’re not doing something else, and you have to think about whether that something else is more beneficial.”

As of June 9, 914 minors curfew violations had been issued this year, more than doubling the 445 violations issued by the same time last year, police said. Nearly a quarter of the violations this year have come from the 12th Police District in Southwest Philly, data show.

Police did not provide the age or racial breakdown on those who were stopped by police.

Inspector Francis Healy, adviser to Police Commissioner Danielle Outlaw, previously said the department “fully supports the amendment.”

“If we can save one kid from being shot out there, this is a huge win and well worth all our effort,” Healy said.

Staff writer Chris Brennan contributed to this article.