Requiring teens to get learner’s permits or go through other interim stages before gaining their driver’s licenses reduces auto accidents among young drivers – though they continue to have the highest rate of fatal crashes.

Twelve studies released Tuesday by the nonprofit National Safety Council found that graduated driver’s license programs reduce teen crash rates by as much as 33 percent. One study found fatalities involving teen drivers plummeted 58 percent.

Among all drivers, however, teenagers still had the highest rate of fatal crashes – 71 fatal crashes out of 100,000 for 16-year-olds; 63 out of 100,000 for 18-year-olds; 59 out of 100,000 for 17-year-olds; and 57 out of 100,000 for 19-year-olds.

At least 38 states and the District of Columbia have three-tiered graduated driver’s license programs. While they vary, a typical program generally gives teens their licenses after they have received a learner’s permit and an intermediate license.

A learner’s permit requires teens to drive with an adult, while an intermediate license may allow teens to drive unsupervised but only during daylight hours.

“We know now, and we have the evidence, that GDL can be and is successful,” said Chuck Hurley, vice president of the council’s transportation safety group.

The National Safety Council, an Illinois-based nonprofit organization that lobbies the government on safety issues, examined graduated driver’s license programs in the United States, Canada and New Zealand, which was the first country to adopt a graduated license system in 1984.

The studies indicated that such programs reduce teen crash rates whenever they are implemented.

For instance, in Florida, which was the first state to adopt a three-tiered licensing system in 1996, there was a 9 percent reduction in fatal and injury crashes for 15- to 17-year-olds from 1995 to 1997, according to a 2000 study published in the periodical Accident Analysis and Prevention.

In Pennsylvania, crashes involving 16-year-old drivers dropped 27 percent between 1999 and 2000, while fatalities in that group dropped by 58 percent, according to a 2002 study by the Pennsylvania Department of Transportation.

Researchers say the most likely cause of the drop in accident rates is that provisional licenses keep teens off the road, particularly at night.

One-third of fatal crashes involving teens occur between 9 p.m. and 6 a.m., even though only 15 percent of the miles driven by teens are driven between those hours, according to the National Safety Council.

But researchers say it’s also possible teens are driving more carefully under the restrictions, or that graduated licensing programs make parents more aware of safety restrictions and more likely to enforce them.