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Study: Teen Driving Law Reduced Crashes By 68 Percent

teen driver gets keys

An analysis of California’s teen-age graduated driver licensing law (GDL) implemented 15 years ago shows that it has been effective in reducing fatal and injury collisions for novice drivers.  The number of at-fault fatal and injury crashes for 16-year-old teen drivers declined by 68 percent, according to the Automobile Club of Southern California. Among 17-year-olds, the drop was 51 percent. 


The Brady-Jared Teen Driver Safety Act that established the state’s GDL system was sponsored by California’s AAA clubs.  The law, passed in 1997 and implemented in 1998, eases novice teen drivers into the driving experience, and reduces their exposure to the most dangerous risks by imposing restrictions that prohibited young passengers and limit nighttime driving.  


The Auto Club’s analysis also coincides with “The 100 Deadliest Days of Summer”– the period between Memorial Day and Labor Day – considered to be high-risk for teen-age drivers since seven of the top 10 deadliest driving days of the year occur in summer.


“While an early Auto Club analysis of the law in 2001 showed California’s law to be effective, GDL has now been around for 15 years,” said the Automobile Club of Southern California’s Senior Traffic Safety Researcher Steven A. Bloch, Ph.D. “The current analysis – more than 10 years later – shows that the law continues to be effective in saving lives.”


In 1998, the year before the first teens received provisional licenses under the GDL law, 18,000 California teens killed or injured in vehicle crashes annually.  In 2010 (most recent data available), about 8,000 teens ages 16 and 17 were killed or injured statewide in motor vehicles.


“Parental involvement, more time behind the wheel, removing young passengers from the vehicle and limiting late night driving have all helped reduce teen driver crashes and are all part of GDL,” said Bloch.  “We need parents and teens to continue to understand and follow the law to further reduce crashes.”


California’s Graduated Driver License law requires that teens:


--hold an instruction permit for at least six months and, during that time, complete 50 hours of supervised driving, including 10 hours at night.  A parent or guardian must certify in writing that the hours were completed.


--limit passengers during the first year of licensure.  Unless a licensed driver over 25 is in the vehicle, a new teen driver cannot carry passengers under the age of 20.


--not drive between 11 p.m. and 5 a.m. for the first 12 months of a provisional license, with very limited exceptions.


Under GDL, some decline in fatal and injury crashes among 16-17-year-olds can be attributed to a reduction in driver licensing among teens in this group.  Some decline also can be attributed to the recession/weak economy and automotive safety improvements that affect all drivers – more air bags, better brakes and stability control systems.  But, according to Bloch, after controlling for these changes, the drop in crash rates among teens from 1998-2010 still demonstrates GDL is effective.


Delaying licenses until teens become older doesn’t appear to have an effect on their crash rates. The analysis controlled for changes in teen driver licensing by computing crash rates per licensed driver.  From 1998-2010, there was a 41 percent drop in driver licenses among 16-year-olds and a 24 percent drop in licenses among 17-year-olds. The 18 and 19-year-olds increased their licensing by 6 percent and 27 percent respectively.  Examining at-fault fatal and injury crash rates per licensed drivers shows that, crash rates among:


  • 16-year-olds dropped 45 percent (from 3.72 crashes per 100 drivers to 2.04).
  • 17-year-olds dropped 35 percent (from 2.87 to 1.87).
  • 18-year-olds dropped 21 percent (from 2.47 to 1.96)
  • 19-year-olds dropped 22 percent (from 1.99 to 1.56).


To control for safety and economic trends that affect all drivers, the analysis also looked at changes in crash rates among teen drivers and those ages 20 and older.   From 1998-2010, there was a 23 percent drop in at-fault fatal and injury crash rates per driver among drivers ages 20 and older.  That change (23 percent) was far exceeded by the sharp drop in crash rates among novice teen drivers (45 percent among 16-year-olds and 35 percent among 17-year-olds).


“That makes a pretty strong case that GDL played a significant role in redu­cing teen crash rates among 16 and 17-year-olds,” concluded Bloch, adding that “Crash rate reductions among 16-year-olds were twice those of older teen drivers (18- and 19-year-olds) not covered by GDL and of older drivers in general.  But teens are still over-represented in car crashes and the Auto Club supports legislative efforts to strengthen the law with enhancements to the age requirement, night driving limits and passenger components.”


More information about state’s teen driver law can be found at, or to obtain an Auto Club parent-teen agreement or a graduated driver licensing law brochure, members can call the Auto Club at 800-541-5552.


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The Automobile Club of Southern California is a member club affiliated with the American Automobile Association (AAA) national federation and serves members in the following California counties: Inyo, Imperial, Kern, Los Angeles, Mono, Orange, Riverside, San Bernardino, San Diego, San Luis Obispo, Santa Barbara, Tulare, and Ventura.