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Effectiveness: 5 Star Cost: $
Use: High
Time: Medium

GDL is a three-phase system for beginning drivers, consisting of a learner’s permit, an intermediate license, and a full license. A learner’s permit allows driving only while supervised by a fully licensed driver. An intermediate license allows unsupervised driving under certain restrictions. These usually include limits on driving at night or with teenage passengers. The learner’s permit and the intermediate license each must be held for a specified minimum period of time.

GDL serves two functions: reducing risk and reducing exposure. GDL allows beginning drivers to acquire driving experience in less-risky situations and under direct supervision during the learner’s permit phase. It helps young drivers avoid dangerous conditions such as late-night driving or driving with teenage passengers in the vehicle during the intermediate phase. GDL delays full licensure by requiring a minimum time in both the learner’s permit and intermediate phases. Compared to earlier requirements in many jurisdictions, where beginning drivers could receive a full license at age 16 (and sometimes earlier) by passing a minimal driving test, GDL reduces the amount of unsupervised driving by 16-year-olds. GDL also ensures that young drivers are more mature when they receive their first unrestricted license. Based on a national survey, most parents (61 to 98% depending on the policy) support GDL policies that are as strong as, or even stronger, than policies currently in place in the United States (Williams et al., 2011).

All States now have some form of GDL in place. IIHS (2021c) documents GDL laws in each State and the website is updated monthly. The papers in the special issue of the 2007 Journal of Safety Research (Editorial Board, 2007) describe GDL’s history, components, effectiveness, parental roles, potential enhancements, and research needs. Strategies for implementing or improving GDL systems are described in NCHRP’s Guide for Reducing Collisions Involving Young Drivers (Goodwin et al., 2007, strategies A1 through A5). See also NHTSA’s Traffic Safety Facts on GDL (NHTSA, 2008) and Teen Driver Crashes: A Report to Congress (Compton & Ellison-Potter, 2008), and the Traffic Injury Research Foundation’s New GDL Framework: Evidence Base to Integrate Novice Driver Strategies (Mayhew et al., 2014).


All States and the District of Columbia had some GDL components in place as of November 2021. In addition, all States and the District of Columbia had a three-phase GDL system in place (IIHS, 2021b).


GDL’s effectiveness in reducing young driver crashes and fatalities has been well-documented (Baker et al., 2007; Chapman et al., 2014; Chaudhary et al., 2018; Fell et al., 2011; Lyon et al., 2012; Masten et al., 2011; Masten et al., 2013; Masten et al., 2015; McCartt et al., 2010; Russell et al., 2011; Shope, 2007; Simpson, 2003; Williams, 2017). The most restrictive GDL programs—those with at least a 6-month holding period during the learner stage, a night restriction beginning no later than 10 p.m., and restrictions allowing no more than one teen passenger—are associated with a 38% reduction in fatal crashes and a 40% reduction in injury crashes among 16-year-old drivers (Baker et al., 2007). In addition to reducing crashes, GDL is associated with declines in hospitalization rates and charges for 16-year-old drivers (Margolis et al., 2007; Pressley et al., 2009) and healthcare resource utilization for drivers 16 to 20 years old and their occupants (Conner & Smith, 2017).


GDL’s primary costs result from the intermediate license, which adds to licensing agency workload by requiring each beginning young driver to receive three licenses in succession rather than two. These costs are typically covered by small fees charged by the licensing agency.

Time to implement:

 Licensing changes typically require up to a year to plan, publicize, and implement.

Other issues:

  • Age of licensure: Over the years, there has been discussion about the most appropriate age for allowing teenagers to drive independently (Foss et al., 2014; Williams, 2009; Williams et al., 2013). Licensing ages vary from State to State, from a low of 14½ in South Dakota to a high of 17 in New Jersey. Delaying licensure, either through higher entry ages or GDL requirements such as extended learner stages, can reduce young driver crashes (Foss et al., 2014). For example, New Jersey’s GDL system has eliminated most crashes among 16-year-old drivers and has reduced crashes among 17-year-olds by 16% (Williams et al., 2010).
  • Applying GDL to older novices: In most States, GDL only applies to drivers under the age of 18. If teens delay licensure until age 18 or older, they miss the safety benefits of GDL. Tefft and Foss (2019) report approximately one-third of first-time license holders in the United States are 18 or older. In addition, older novice drivers, 18 to 20 years old, have increased crash rates immediately after licensure like that of 17-year-old novice drivers (Curry, Metzger, et al., 2017).  This indicates there might be value in extending GDL provisions to older novice drivers 20 years old and younger. A recent study examined Indiana’s GDL that extended its nighttime driving restriction and passenger restriction to include all newly licensed drivers under 21 years old and found crashes were actually higher among drivers licensed under the new system (Wang, Foss, Goodwin, et al., 2020). However, the nighttime and passenger restrictions were in addition to an already implemented 6-month learner permit for all drivers under 21 so it was not possible to determine the independent effect of the 6 month learner period for older novices. More research is needed to determine whether GDL—which was designed for teenagers—can benefit older novices who may have different life circumstances (e.g., living away from home) and different driving needs (e.g., full-time jobs).