Recent expert consensus, A New GDL Framework: Planning for the Future, funded by the Traffic Injury Foundation, recommends a minimum GDL entry age of 17 years and a holding period of 12 months for  an intermediate license. To qualify for MAP-21 GDL incentive funding, a state needs to require a minimum entry age of 17 years, with that driver holding the license for a period of 6 months or until age 18. However, not all states meet this standard: Some start the licensing process earlier and with shorter minimum holding periods that can place novice drivers at increased risk of crashing.

Expand GDL Age Requirements

CHOP research, led by Principal Investigator Allison E. Curry, PhD, MPH and funded by the AAA Foundation for Traffic Safety, compared crash rates of older and younger novice drivers over the initial four years of licensure using a longitudinal analysis of more than 1 million novice drivers in NJ who got licensed from January 2006 through December 2014. Currently, NJ has provided the best opportunity to study this important topic. NJ is only one of three jurisdictions in the US that apply full GDL rules, including nighttime and passenger restrictions, to all novice drivers under age 21.

The researchers’ findings in New Jersey suggest that expanding GDL requirements may make newly-licensed 17- to 20-year-old drivers safer and the potential for added benefits of beginning the nighttime restriction at 9 p.m. Conversely, there was a lack of compelling evidence for additional GDL policies for drivers licensed at age 21 to 24 and no evidence to indicate a need for additional GDL policies for NJ novice drivers ages 25 years and older.

Evidence concerning licensing patterns, socioeconomic disparities, and public opinion also indicates that states should consider expanding their GDL to age 21 in order to protect the substantial proportion of teens that get licensed at or after 18 years old.

At least one in three teens get a license at or after age 18 and, thus, do so without the protective benefits of GDL, beyond basic learner requirements (New Jersey is the exception). In two very different studies – one an analysis of New Jersey's administrative licensing database led by Dr. Curry, the other an examination of a nationally representative survey of teens led by Brian Tefft, PhD of the AAA Foundation for Traffic Safety -- researchers found similar and stark differences in socioeconomic status.

Disparities in Licensing

While virtually all 18- to 20-year-old NJ residents in the state's highest income areas are licensed by age 21, more than one in three residents in the lowest income areas are not licensed by that age. 40% of all New Jersey residents – and half of those eventually licensed by age 21 – obtain a license in the first month they are eligible, but this looks very different for income by zip code:

• Among those living in the lowest-income zip codes, only 13% are licensed within one month of turning 17, and only 36% are licensed by age 18.
  
   
• 65% of those living in NJ's highest-income zip codes are licensed immediately upon turning 17, and 78% are licensed within six months.

In the national survey of teens ages 18 to 20, 54% were licensed by their 18th birthday. But only 25% of teens from households with an annual income of less than $20,000 were licensed by age 18. Also in the national survey, 67% of white teens, 37% of black teens, and 29% of Hispanic teens were licensed by age 18. The NJ study had a similar assessment.

Later Licensure is a Steady Trend

The NJ study found similar rates of licensure between 2006 and 2011. Fewer than one in four teens cite reasons related to special driving requirements for young new drivers in their decision to get licensed later. Although patterns differ by state, later licensing has increased nationally in recent years, most likely as a result of the recent economic recession. Teens cite not having a car, the cost of gas, and the cost of maintaining a vehicle as primary reasons for waiting to get licensed. Recent studies have found a strong link between socioeconomic status and licensing age. Collectively, these findings have raised concern that teens in lower-income households may be missing the protective benefits of GDL.