Research In Action

Because New Jersey requires all newly-licensed drivers under age 21 to abide by full Graduated Driver Licensing (GDL) provisions, we recently had the great opportunity to examine the influence of licensing age, driving experience, and GDL license phase on crash rates of novice drivers licensed at ages 17 through 20 without the confounding effect of GDL. (In most other states, 17-year-olds are licensed under GDL while 18- to 20-year-olds are not.) Using a unique database we developed that linked NJ’s state-level licensing and crash records, we focused on drivers that first obtained their Intermediate License at age 17 to 20 from 2006 to 2009.

Age AND Experience Matter with Crash Rates

It is well known that novice drivers as a group--regardless of age--are at higher risk of crashing than experienced drivers. We also know that novice teen drivers have the highest crash risk. In general we found that:

1. Teens licensed at older ages have lower crash rates than teens licensed immediately upon becoming eligible.
2. Among teens of the same age, those who have been licensed longer have lower crash rates. 

As described in a recent AAA Foundation for Traffic Safety report, there are benefits to a higher licensing age:

• As compared to drivers licensed at 17 years and 0 months of age, crash rates in the first month of licensure were 18% lower for drivers licensed between 17 years and 1 month and 17 years and 11 months of age, 20% lower for drivers licensed at age 18, and 30% lower for drivers licensed at ages 19 through 20.

On-Road Experience Also Important

• Teens licensed at 17 years 0 months who had been driving for a year had crash rates 25 to 36% lower than the initial crash rates for newly-licensed 18-year-old drivers.

Even though later-licensed teens initially had lower crash rates in the first month as compared to those licensed younger, they still had elevated crash rates that decreased steadily over their first 12 months of driving independently, eventually closing in on the lower crash rates of the drivers who had been licensed longer.

The complex interaction between age and experience--that is, the fact that the association between driving experience and crash rates depend on age and visa-versa--highlights the importance of considering these two factors in tandem and is discussed more thoroughly in the report.

Why States Should Explore Adding 2 Provisions to Their GDL Program: 

1. Raise the minimum age for Intermediate Licensure. MAP-21 recommends a minimum age of 17, but only New Jersey currently has this provision.
2. Extend full GDL requirements to all novice drivers through age 20. This includes an Intermediate License holding period of 6 to 12 months to initially protect older novice drivers from risky driving situations as they gain driving skill and experience. 

Because delayed licensure among young drivers is tied to socioeconomic disparities, this is an important conversation to have in state capitals.

All age cohorts in this study experienced an abrupt spike in crash rates when they transitioned from an Intermediate to Full License. While there is more work to be done to pinpoint the reason for this brief but sharp increase, advocates should consider these transition points as important opportunities to reinforce safe driving messages.