REYKJAVIK, Iceland (AP) -- The clock strikes 10 p.m. on a Friday night when the "Parent Patrol" enters a popular playground in suburban Reykjavik. The teens turn down the music and reach for their phones to check the time: It's ticking into curfew.
Every weekend, parents all over the Icelandic capital embark on a two-hour evening walk around their neighborhood, checking on youth hangouts.
The walk is one step toward Iceland's success into turning around a crisis in teenage drinking. Focusing on local participation and promoting more music and sports options for students, the island nation in the North Atlantic has dried up a teenage culture of drinking and smoking. Icelandic teens now have one of the lowest rates of substance abuse in Europe.
Other countries are taking notice. The Icelandic Centre for Social Research and Analysis, the institute pioneering the project for the past two decades, says it currently advises 100 communities in 23 countries, from Finland to Chile, on cutting teen substance abuse.
"The key to success is to create healthy communities and by that get healthy individuals," said Inga Dora Sigfusdottir, a sociology professor who founded the "Youth of Iceland" program, which now has rebranded as "Planet Youth."
The secret, she says, is to keep young people busy and parents engaged without talking much about drugs or alcohol.
That stands in sharp contrast to other anti-abuse programs, which try to sway teenagers with school lectures and scary, disgusting ads showing smokers' rotten lungs or eggs in a frying pan to represent an intoxicated brain.
"Telling teenagers not to use drugs can backlash and actually get them curious to try them," Sigfusdottir said.
In 1999, when thousands of teenagers would gather in downtown Reykjavik every weekend, surveys showed 56% of Icelandic 16-year-olds drank alcohol and about as many had tried smoking. Years later, Iceland has the lowest rates for drinking and smoking among the 35 countries measured in the 2015 European School Survey Project on Alcohol and Other Drugs.
On average, 80% of European 16-year-olds have tasted alcohol at least once, compared with 35% in Iceland, the only country where more than half of those students completely abstains from alcohol. Denmark -- another wealthy Nordic country -- has the highest rates of teen drinking, along with Greece, Hungary and the Czech Republic, where 92% to 96% have consumed alcohol.
In the U.S., teen drinking is a significant health concern, because many U.S. teens are driving cars and don't have access to good public transportation like teens in Europe. The U.S. Centers for Disease Control reports that while U.S. high school drinking has declined substantially in the last 20 years to 32.8% in 2015, 17.7% of U.S. high school students still binge drink at least once a month. The CDC also reports that excessive drinking accounts for around 4,300 deaths a year in the U.S. among people under 21.
Reykjavik Mayor Dagur B. Eggertsson said the Icelandic plan "is all about society giving better options" for teens than substance abuse. He believes the wide variety of opportunities that now keep students busy and inspired has dramatically altered the country's youth culture.
Yet better options cost money. Local municipalities like Reykjavik have invested in sport halls, music schools and youth centers. To make the programs widely available, parents are offered a $500 annual voucher toward sports or music programs for their children.
As a teen, Eggertsson remembers taking the bus downtown on weekend nights to wander the streets of Reykjavik "without really going anywhere."
"I remember watching a friend puke behind a police station and fishing another one from the harbor after falling in," the 46-year-old father of four told The Associated Press. "What was socially acceptable then would now be a scandalous headline in the paper."
Today's news articles about teenagers have a different tone: Anxiety and symptoms of depression have never been higher, particularly among girls, where the rate has doubled in the past ten years. Vaping has replaced tobacco use, with about 40% of Icelandic 16-year-olds having tried the electronic cigarettes.
Researchers say the "Planet Youth" prevention model is evolving constantly because it is based on annual surveys to detect trends and measure policy effectiveness.
The group of parents patrolling the Kórar neighborhood -- a lawyer, an advertising agent and a diplomat, among others -- walk across empty parking lots to pass by known teenage hangouts.
By law -- introduced when Icelandic police routinely dealt with alcohol-fueled street gatherings -- children under 12 are not allowed to be outside after 8 p.m. without parents and those 13 to 16 not past 10 p.m. Over summer, when school is out, the curfew is extended by two hours.
"We tell the kids if they are out too late, polite and nice, and then they go home," said Heidar Atlason, a veteran member of the patrol.
Over Iceland's harsh winter, the one parent admits, evenings sometime pass without running into any students. Modern teens meet online rather than outside.