The number of Minnesota teenagers dying in car crashes has plummeted over the past 15 years, a trend that appears to reflect more restrictive licensing laws and changes in teen interests and behavior in the social media era.

A Star Tribune review of state and federal death certificates found that the number of 15- to 19-year-olds who died in motor vehicle crashes dropped from 102 in 2003 to 23 last year, a historic low for the state.

As a public health achievement, that decline matches the sharp reduction in AIDS deaths in Minnesota since 1984 and the historic drop in teen pregnancies since 1990. The drop is so big that it has cut Minnesota's overall child mortality rate — which includes deaths from cancer, influenza and other types of accidents such as falls — even as the adult death rate has increased.

Even more surprising, the Star Tribune analysis found that the per-capita rate of teens dying on Minnesota roads is now lower than the rate for adults. That rate measures deaths regardless of whether crash victims are drivers, passengers or pedestrians.

State traffic safety officials caution against declaring victory, or presuming that teens are now safer drivers. The main reason for the decline, they argue, is that fewer teens are on the roads. The number of licensed teenagers declined from 284,000 in 2003 to 248,000 in 2013, though it has risen back to 256,000, according to state figures.

"Traffic crashes are still one of the leading causes of death among teens," said Gordy Pehrson, a traffic safety coordinator for the Minnesota Department of Public Safety. "We have a long way to go yet."

With respect to teen performance behind the wheel, state officials say the statistics remain troubling. The number of teens hospitalized due to car wrecks also has declined over the past decade, but the rate has increased, considering that there are fewer teens and they are driving less, said Jon Roesler, an injury epidemiologist for the Minnesota Department of Health.

"Kids who are driving, they're more dangerous than ever," he said. "They've got their cellphones with them."

Health officials note that driving deaths have become less common in Minnesota, regardless of the driver's age, due in part to improvements in vehicle safety and trauma response by EMTs and hospitals, as well as a state safety campaign called Toward Zero Deaths.

The decline in teen drivers and deaths also appears to reflect social and policy changes, not just a shrinking demographic of teenagers.

Pehrson said Minnesota's imposition of graduated drivers licensing in 2008 played a role. If teens obtain their provisional driver's license at age 16 or 17, state law now prohibits them from driving with more than one unrelated teen passenger for the first six months, or from driving unsupervised after midnight unless it is necessary for work.

Research in multiple states suggests that such restrictions motivate teens to delay driving until they are 18 or older.

Getting friends out of the car helps new drivers concentrate, Pehrson added.

"An adult passenger is usually another set of eyes. They're experienced drivers and they're … alerting teen drivers to hazards," Pehrson said. "Whereas their peers don't necessarily play that role. Typically they are more of a distractor. They'll pull out their cellphone and say, 'Hey, look at this funny cat video.' "

Apart from changes in the law, teenagers appear to hold different attitudes about driving and its importance. Mobile phones and social media have altered the daily routines of adolescents, who feel comfortable studying, chatting or even dating peers remotely, said Gene Roehlkepartain, a vice president at Search Institute, a Minneapolis child development research center.

"Driving, for many kids, is less of a rite of passage than it used to be," he said.

While some scholars worry that social media causes a loss of face-to-face contact and an overreliance on technology, the trend has contributed to a safer generation of teens. The Minnesota Student Survey, a biennial questionnaire about youth behavior, showed in 2016 that high school juniors are less likely to smoke, drink, fight, have unprotected sex, or drink and drive.

While he is not an expert in traffic safety, Roehlkepartain said today's teens seem to be exercising good judgment, and that this could translate into safer driving. "I don't think we should dismiss the fact that kids may be behaving differently," he said.

Roesler isn't convinced. The prefrontal cortex, the portion of the brain that assesses risk and makes judgments, isn't fully developed until age 25. That means teen drivers will inherently be at a disadvantage, he said.

"You don't have to be a neuroscientist to figure it out. The actuarials have already figured it out," which is why teens pay more for insurance and can't rent cars.

In fact, Roesler convinced his own daughter to delay driving until college. His boss offered to pay his two kids the amount he otherwise would have paid in higher auto insurance premiums, if they postponed getting their licenses as well. One took the money.

State data also show that distractions have replaced drinking as the biggest risk on the road. Teen motor vehicle fatalities related to drinking have dropped from 12 in 2011 to two in 2015, according to the Department of Public Safety, while deaths related to distractions have increased from three to seven.

Texting is an increasing culprit; drivers 20 and younger received 590 traffic citations for texting while driving in 2016, compared to 162 citations in 2011.

Behind-the-wheel and classroom training have evolved with these changes, said Chuck Walerius, a former crash reconstructionist for the Minnesota State Patrol who is now a Safeway driving instructor. Persuading teens to stow their phones has become a focus.

"I think it is making a difference. I hope it is making a difference," he said. "I've knocked on too many parents' doors at 3 o'clock in the morning" to report a child's crash.

Educating parents, too, is part of the state strategy. Pehrson helped create a 90-minute class for parents; the incentive is that drivers need fewer hours of behind-the-wheel practice if their parents complete the session.

"We encourage parents to establish a contract with their teens that tells them what the family rules are," he said. "Hopefully their rules are tighter than the state laws."

Some parents, for example, require teen drivers to lock their phones in the trunk of the car. Others use mobile apps that track where teens are and how fast they're driving.

Kristin Sullivan of Eden Prairie remembers the contract her father drew up, requiring that she pay for insurance and repair costs if she caused a crash. On Thursday, after her oldest son, Joey, completed his final behind-the-wheel practice session, Sullivan said she would probably write him a contract too.

Her son was in no hurry, as he turned 16 in May and could have earned his license months ago. But Sullivan said she is eager for him to drive, and trusts him as a "rules follower" to be conscientious. Making him wait wasn't an option the family considered.

"The two younger kids have activities," she said. "We're a typical busy suburban family and it will be helpful."