Effects of the California graduated driver licensing program.
OBJECTIVE
On July 1, 1998, in an effort to ameliorate the problem of high teenage driver crash rates, California implemented a graduated driver licensing system (GDLS).


METHODS
Data on injury crashes of 16- and 17-year-old drivers from a pre-GDLS year were compared with data from two post-GDLS years. Per-capita crash rate ratios were adjusted for changes in crash rates of 25- to 34-year-old drivers, who were unaffected by the GDLS. Prevented numbers and 95% confidence intervals were estimated.


RESULTS
Fatal or severe injury crash rates were significantly lower during each of the two post-GDLS years (adjusted rate ratios (RR)=0.72 and 0.83, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Significant rate reductions were observed for all crash types, particularly for struck object (RR=0.71 and 0.80, for 2000 vs. 1997 and 2001 vs. 1997, respectively) and non-collision (RR=0.63 and 0.72, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Minor injury crash rates were also lower during post-GDLS years (RR=0.87 and 0.90, for 2000 vs. 1997 and 2001 vs. 1997, respectively). Percent reductions were notably larger during the hours of the late night driving restriction (midnight-5 a.m.) (RR=0.79 and 0.87, for 2000 vs. 1997 and 2001 vs. 1997, respectively).


CONCLUSIONS
The implementation of the California GDLS was followed by large reductions in the rate of injury-producing motor-vehicle crashes.


CONCLUSIONS
This evaluation supports previous evidence that GDLS is an effective countermeasure to adolescent motor-vehicle crashes and their associated injuries. States with a traditional licensing system may prevent adolescent driver crashes by adopting a GDLS. Future studies should examine factors that influence teenager compliance with GDLS provisions and identify approaches to improving compliance.
Rice
Thomas M
TM
Southern California Injury Prevention Research Center, University of California, Los Angeles, School of Public Health, 10911 Weyburn Avenue, Suite 200, 90024, USA. tr@ucla.edu
Peek-Asa
Corinne
C
Kraus
Jess F
JF
D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000293:Adolescent; D000294:Adolescent Behavior; D017677:Age Distribution; D001334:Automobile Driving / Q000592:standards* / Q000706:statistics & numerical data*; D002140:California / Q000453:epidemiology; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008004:Licensure / Q000592:standards* / Q000706:statistics & numerical data*; D008297:Male; D011159:Population Surveillance; D015995:Prevalence; D017678:Sex Distribution; D014947:Wounds and Injuries / Q000453:epidemiology*