Strong graduated driver licensing laws

Graduated driver licensing (GDL) is a three stage system consisting of a learner’s permit, an intermediate license, and a full license (NHTSA-Goodwin 2013). GDL laws are established at the state level and strength varies by state (IIHS-GDL 2014). Strong GDL laws often include strict passenger and nighttime driving limitations, high minimum ages for learner’s permits, intermediate, and full licenses, and/or increased requirements for supervised driving experience between licensing stages (CDC-MV PSR 2013, ). GDL laws usually do not apply to adults (IIHS-GDL 2014).

Expected Beneficial Outcomes (Rated)

  • Reduced fatal and non-fatal injuries

  • Reduced crashes

Evidence of Effectiveness

There is strong evidence that strong graduated driver licensing (GDL) laws reduce crashes and fatalities more than weaker laws (, IIHS-GDL 2014), especially for 15-year old () and 16-year-old drivers (, , ). Strong laws appear to reduce fatal crashes through young adulthood (IIHS-GDL 2014, ). Hispanic youth may not benefit from GDL laws as much as non-Hispanic youth ().

GDL laws with nighttime driving restrictions can reduce crashes and fatalities more than those without such restrictions (, ). Restrictions beginning at 9 or 10pm may prevent more crashes and fatalities than those beginning later (, IIHS-Trempel 2009); 16-year-old drivers have been shown to crash nearly three times as frequently after 9pm than before 9pm ().

GDLs with passenger restrictions during the provisional license period can reduce crashes and fatalities more than those without such restrictions (, , , IIHS-Trempel 2009). Some studies suggest that laws allowing no teenage passengers prevent the most fatalities (IIHS-GDL 2014), while others suggest allowing one teenage passenger is safest. Young passengers can increase distraction, risk-taking, and fatalities among teenage drivers; passengers over age 35, however, can reduce risk and prevent fatalities ().

Increasing the minimum permit or licensure age can reduce fatal crash rates for 15 to 17-year-olds in some circumstances (IIHS-GDL 2014, NHTSA-Goodwin 2013, ). Requiring more supervised practice hours may also reduce crashes (IIHS-GDL 2014). Surveys indicate that parents may not know the importance of exposing novice drivers to a variety of conditions. North Carolina-based studies indicate that most practice driving occurs in residential areas with light traffic, and that many accidents during the first month of unsupervised driving reflect a failure to master basic maneuvers during the learning period ().

Teens generally comply with GDL laws when both parents and teens consider requirements reasonable (NHTSA-Goodwin 2013). National polling indicates that nighttime and passenger restrictions () and learner permit holding periods are popular (NHTSA-Goodwin 2013).

Implementing strengthened GDL laws can cost very little. States typically require about six months to implement changes and notify residents (NHTSA-Goodwin 2013).  

Impact on Disparities

Likely to increase disparities

Implementation Examples

All states have GDL laws, but strength and comprehensiveness vary widely (). Most states allow unsupervised driving at age 16; minimum ages range from 14 and 3 months to 17. 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. Five states have no passenger restrictions during intermediate licensure, while 15 states and Washington DC allow no passengers or no young passengers except family members (IIHS-GDL).

Experts recommend a minimum age of 16 for a learner’s permit (IIHS-GDL, CDC-MV PSR 2013), at least six months (CDC-MV PSR 2013) or 70 practice hours and a minimum age of 17 (IIHS-GDL) before advancing to the intermediate stage, and a minimum age of 18 for full licensure (CDC-MV PSR 2013). During intermediate licensure, experts recommend nighttime restrictions begin by 8pm (IIHS-GDL) or 10pm (CDC-MV PSR 2013) and a limit of one (CDC-MV PSR 2013) or zero teen passengers (IIHS-GDL). No state law includes all of the strongest provisions that experts recommend (IIHS-GDL 2014).

Implementation Resources

PHLR-GDL - Public Health Law Research (PHLR). Graduated driver licensing laws.

IIHS-GDL calculator - Insurance Institute for Highway Safety (IIHS). GDL crash reduction calculator.

Citations - Evidence

* Journal subscription may be required for access.

McCartt 2010* - McCartt AT, Hellinga LA, Strouse LM, Farmer CM. Long-term effects of handheld cell phone laws on driver handheld cell phone use. Traffic Injury Prevention. 2010;11(2):133–41.

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, DC: National Highway Traffic Safety Administration (NHTSA), US Department of Transportation (US DOT); 2013.

Fell 2011* - Fell JC, Jones K, Romano E, Voas R. An evaluation of graduated driver licensing effects on fatal crash involvements of young drivers in the United States. Traffic Injury Prevention. 2011;12(5):423–31.

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.

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

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.

IIHS-GDL 2014 - Insurance Institute for Highway Safety (IIHS). Graduated driver licensing (GDL). 2014.

Citations - Implementation Examples

* Journal subscription may be required for access.

CDC-MV PSR 2013 - Centers for Disease Control and Prevention (CDC). Motor vehicle injuries: Prevention status reports (PSR). 2013.

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.

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

IIHS-GDL 2014 - Insurance Institute for Highway Safety (IIHS). Graduated driver licensing (GDL). 2014.

Date Last Updated

Mar 26, 2015