BOSTON (CBS) — New research finds that strict driver- licensing laws in Massachusetts have helped to prevent sleep-related crashes and injuries among teenage drivers.

In 2007, the state introduced regulations for junior drivers that ordered harsher penalties for unsupervised nighttime driving and required drowsy driving education.

Motor vehicle crashes are the leading cause of death for teenagers in the United States and around the world, so the study results were welcome news to well-known sleep specialist Dr. Charles Czeisler of Brigham and Women’s Hospital.

“In the eight years since the passage of this legislation, the revised junior operator law has prevented about 320 fatal and incapacitating injuries and 13,000 motor vehicle crashes,” he told WBZ NewsRadio 1030’s Diane Stern.

Cseizler says that overall, police reported night-time crashes decreased in 16 to 17-year-old drivers by 29 percent after the Massachusetts law was amended. The addition of drowsy drivers ed made a difference.

Older people who’ve been studied had fewer lapses of attention because their sleep switches break down with age.

“Whereas in the young people, that switch is working well, it’s the most sensitive that it’s ever going to be in your life,” Cseizler said.

He says a junior driver losing their license is a powerful motivator compared to the earlier punishment.

“It’s a lot different than a $35 fine that most likely their parents will pay,” he said.

WBZ NewsRadio 1030’s Diane Stern reports: