WASHINGTON — When a novice teen driver dies in a crash, odds increasingly are that there is another teenager in the car, new research shows.

For more than a decade, states have been imposing restrictions on teenage drivers that likely deserve credit for an overall decline in teenage traffic fatalities. But a study released Thursday shows that 15- to 17-year-old drivers are almost eight times more likely to get into a fatal accident while carrying two or more teenage passengers.

The analysis of 10 years of national traffic data notes that the 30 percent increase in deaths when other teens are present came at “the same time text messaging exploded in American society.”

“We can’t scientifically state that there’s a direct link between these two things yet, but it seems reasonable to suspect a connection,” said Russell Henk, a researcher at the Texas A&M Transportation Institute, or TTI, who wrote the study.

Drivers age 19 and under are three times more likely to die in accidents, and traffic fatalities are the leading cause of death in that age group.

From 2002 to 2011, the number of novice teen drivers in fatal accidents dropped by 60 percent, but the percentage of fatalities that occurred when other teens were in the vehicle increased each year.

“Novice drivers (15 to 17 years old) are at a distinct disadvantage, not only because of their limited driving experience, but also because of their incomplete brain development,” the TTI study says. “Research has found that the prefrontal cortex of the brain — the region responsible for weighing the consequences of risky behavior — is the last part of the brain to develop.”