Strong graduated driver licensing laws

Evidence Rating  
Evidence rating: Scientifically Supported

Strategies with this rating are most likely to make a difference. These strategies have been tested in many robust studies with consistently positive results.

Health Factors  
Decision Makers
Date last updated

Graduated driver licensing (GDL) is a three-stage system that allows young drivers to gain driving experience, consisting of a supervised learner’s permit, an intermediate (probationary) license, and a full license1. GDL laws are established at the state level and strength varies by state1. Strong GDL laws often include strict passenger and nighttime driving limitations during the intermediate license period, higher minimum ages for learner’s permits, intermediate, and full licenses, and/or increased requirements for supervised driving experience between licensing stages2, 3. GDL laws usually do not apply to adults1.

What could this strategy improve?

Expected Benefits

Our evidence rating is based on the likelihood of achieving these outcomes:

  • Reduced fatal and non-fatal injuries

  • Reduced crashes

Potential Benefits

Our evidence rating is not based on these outcomes, but these benefits may also be possible:

  • Reduced teen births

  • Reduced crime

  • Reduced emergency room visits

What does the research say about effectiveness?

There is strong evidence that strong graduated driver licensing (GDL) laws reduce crashes and fatalities more than weaker laws for 15-17 year old drivers3, 4, 5, 6, 7, 8, 9.

GDL laws with nighttime driving restrictions4, 6, 8, 10 and those with passenger restrictions during the intermediate license period can reduce crashes and fatalities more than those without such restrictions3, 4, 6, 11. Nighttime restrictions beginning at 9 or 10pm may prevent more crashes and fatalities than those beginning later10, 11, 12, 13, 14, 15; 16 year old drivers have been shown to crash nearly three times as frequently after 9pm than before16. Among drivers ages 15-17, GDL laws that ban or allow only one teenage passenger can reduce fatal crashes more than laws that allow two or more teenage passengers or have no passenger restrictions6, 7, 8. Young passengers can increase distraction, risk-taking, and fatalities among teenage drivers; passengers over age 35, however, can reduce risk and prevent fatalities12. An Ohio-based study indicates that enhancement of nighttime and passenger restrictions may reduce motor vehicle crash-related ED visits and hospitalizations17. Strong nighttime driving restrictions may also reduce fertility for teen mothers ages 16-1818 and arrests among teenagers ages 16-1719.

Increasing the minimum age for permits or full licensure can reduce fatal crash rates for 15-17 year olds in some circumstances6, 12, 20. GDL laws requiring a longer learner’s permit holding period can reduce fatal crashes more than GDL laws requiring a shorter permit holding period4, 7. Prohibiting an intermediate license until 16.5 years old or older can reduce driver fatalities among 16 year old drivers compared to allowing such licensing at an earlier age5, 10. Strong laws appear to reduce fatal crashes among drivers ages 18-196, 16. Experts recommend extending strong GDL policies to all novice drivers under age 214, 8, 14, 21.

Available evidence indicates mixed effects on crashes of requiring more supervised practice hours5, 7, 20. Studies of teen drivers at a learner stage and their parents report that parents are less likely to talk about the importance of exposing novice drivers to a variety of conditions with their children and that most practice driving occurs in residential areas with light traffic, resulting in less experience with demanding driving situations during the learning period12. Teens generally comply with GDL laws when both parents and teens consider requirements reasonable20.

Overall, many states have experienced reductions in crashes, fatalities, and injuries after they adopt GDL laws4, 22, 23, 24; however, effect sizes tend to vary by strength level of GDL laws in each state10. A New Jersey-based study indicates that GDL implementation with comprehensive public awareness campaigns and targeted enforcement can be more effective in decreasing fatalities among teen drivers than GDL implementation alone9.

A nationwide study reports that adopting GDL laws has no impact on fatal crash rates among Hispanic youth ages 15-17 whereas such laws show reductions in fatal crashes for white, black, and Asian youth25; more research is needed to confirm effects in different race and ethnic groups.

How could this strategy impact health disparities? This strategy is rated no impact on disparities likely.
Implementation Examples

All states have GDL laws, but strength and comprehensiveness vary widely26. No state law includes all of the strongest provisions that experts recommend26. As of February 2021, most states allow unsupervised driving at age 16; minimum ages range from 14.5 in South Dakota to 17 in New Jersey. During intermediate licensure, most state prohibit unsupervised nighttime driving beginning at 11pm or midnight; restrictions range from no restriction in Vermont to earlier than 9pm in South Carolina and Idaho. Four states have no passenger restrictions during intermediate licensure, while 16 states and Washington, D.C. allow no passengers or no young passengers except family members. The required minimum hours of supervised driving ranges from none in Arizona, Mississippi, and New Jersey to 70 hours in Maine26.

Experts recommend a minimum age of 16 for a learner’s permit with a mandatory holding period of at least 12 months, at least 70 supervised practice hours, a minimum age of 17 before advancing to the intermediate stage, a minimum age of 18 for full licensure, and nighttime driving restrictions between 10pm and 5am and a limit of one or zero teen passengers during intermediate licensure1, 2.

States typically require about six months to implement changes and notify residents20.

Implementation Resources

IIHS-GDL calculator - Insurance Institute for Highway Safety (IIHS). Graduated licensing calculator.

GHSA-Teen and novice drivers - Governors Highway Safety Association (GHSA). Teen and novice drivers.

CDC-GDL planning guide - Centers for Disease Control and Prevention (CDC). Graduated Driver Licensing System Planning Guide. 2016.


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1 IIHS-GDL - Insurance Institute for Highway Safety (IIHS). Graduated driver licensing.

2 CDC-PSR 2015 - Centers for Disease Control and Prevention (CDC). Prevention status reports (PSR) 2015: Motor vehicle injuries.

3 Fell 2011 - Fell JC, Todd M, Voas RB. A national evaluation of the nighttime and passenger restriction components of graduated driver licensing. Journal of Safety Research. 2011;42(4):283-90.

4 Williams 2017a - Williams AF. Graduated driver licensing (GDL) in the United States in 2016: A literature review and commentary. Journal of Safety Research. 2017;63:29-41.

5 Gilpin 2019 - Gilpin G. Teen driver licensure provisions, licensing, and vehicular fatalities. Journal of Health Economics. 2019;66:54-70.

6 McCartt 2010 - McCartt AT, Teoh ER, Fields M, Braitman KA, Hellinga LA. Graduated licensing laws and fatal crashes of teenage drivers: A national study. Traffic Injury Prevention. June 2010.

7 Masten 2013 - Masten SV, Foss RD, Marshall SW. Graduated driver licensing program component calibrations and their association with fatal crash involvement. Accident Analysis & Prevention. 2013;57:105-113.

8 Conner 2017a - Conner KA, Smith GA. An evaluation of the effect of Ohio’s graduated driver licensing law on motor vehicle crashes and crash outcomes involving drivers 16 to 20 years of age. Traffic Injury Prevention. 2017;18(4):344-50.

9 Bonne 2018 - Bonne S, Suber I, Anderson A, Livingston DH. Implementation is not enough: Graduated drivers licensing benefits from a comprehensive enforcement, education, and awareness campaigns. Journal of Trauma and Acute Care Surgery. 2018;85(4):704-10.

10 Zhu 2016a - Zhu M, Zhao S, Long DL, Curry AE. Association of graduated driver licensing with driver, non-driver, and total fatalities among adolescents. American Journal of Preventive Medicine. 2016;51(1):63-70.

11 IIHS-Trempel 2009 - Trempel RE. Graduated driver licensing laws and insurance collision claim frequencies of teenage drivers. Arlington, VA: Insurance Institute for Highway Safety (IIHS), Highway Loss Data Institute (HLDI); 2009.

12 Williams 2012 - Williams AF, Tefft BC, Grabowski JG. Graduated driver licensing research, 2010-present. Journal of Safety Research. 2012;43(3):195–203.

13 Mayhew 2016 - Mayhew DR, Williams AF, Robertson R, Vanlaar W. Better integrating driver education and training within a new graduated driver licensing framework in North America. Recherche Transports Sécurit. 2016;32:97-105.

14 Curry 2017a - Curry AE, Metzger KB, Williams AF, Tefft BC. Comparison of older and younger novice driver crash rates: Informing the need for extended graduated driver licensing restrictions. Accident Analysis and Prevention. 2017;108:66-73.

15 CDC MMWR-Shults 2016 - Shults RA, Williams AF. Graduated driver licensing night driving restrictions and drivers aged 16 or 17 years involved in fatal night crashes - United States. Morbidity and Mortality Weekly Report (MMWR). 2016;65(29):725-730.

16 Steadman 2014 - Steadman M, Bush JK, Thygerson SM, Barnes MD. Graduated driver licensing provisions: An analysis of state policies and what works. Traffic Injury Prevention. 2014;15(4):343–8.

17 Conner 2018a - Conner KA, Smith GA. Decreased healthcare resource utilization associated with enhancement of a state graduated driver licensing law. Journal of Transport and Health. 2018;10:213-24.

18 Deza 2019 - Deza M. Graduated driver licensing and teen fertility. Economics and Human Biology. 2019;35:51-62.

19 Deza 2016 - Deza M, Litwok D. Do nighttime driving restrictions reduce criminal participation among teenagers? Evidence from graduated driver licensing. Journal of Policy Analysis and Management. 2016;35(2):306-32.

20 NHTSA-Goodwin 2013 - Goodwin A, Sandt B, Hall W, Thomas L, O’Brien N, Summerlin D. Countermeasures that work: A highway safety countermeasure guide for state highway safety offices, 7th edition. Washington, D.C.: National Highway Traffic Safety Administration (NHTSA), U.S. Department of Transportation (U.S. DOT); 2013.

21 Curry 2017b - Curry AE, Foss RD, Williams AF. Graduated driver licensing for older novice drivers: Critical analysis of the issues. American Journal of Preventive Medicine. 2017;53(6):923-927.

22 Salam 2016 - Salam RA, Arshad A, Das JK, et al. Interventions to prevent unintentional injuries among adolescents: A systematic review and meta-analysis. Journal of Adolescent Health. 2016;59(4):S76-S87.

23 NHTSA-Masten 2015 - Masten SV, Thomas FD, Korbelak KT, Peck RC, Blomberg RD. Meta-analysis of graduated driver licensing laws. Washington, D.C.: National Highway Traffic Safety Administration (NHTSA), U.S. Department of Transportation (U.S. DOT); 2015.

24 Cochrane-Russell 2011 - Russell KF, Vandermeer B, Hartling L. Graduated driver licensing for reducing motor vehicle crashes among young drivers. Cochrane Database of Systematic Reviews. 2011;(10):CD003300.

25 Romano 2011 - Romano E, Fell J, Voas R. The role of race and ethnicity on the effect of graduated driver licensing laws in the United States. Association for the Advancement of Automotive Medicine. 2011;55:51-61.

26 IIHS-GDL laws - Insurance Institute for Highway Safety (IIHS). Graduated licensing laws by state.