AAA FOUNDATION FOR TRAFFIC SAFETY
Teenage drivers are involved in more crashes per mile driven than drivers of any other age group; drivers aged 16-17 are involved in about seven times as many crashes per mile driven as drivers in their forties, fifties, or sixties (General Estimates System, 2012; National Household Travel Survey, 2011). While the oldest drivers have a higher rate of driver deaths per mile driven—mostly attributable to their increased likelihood of dying if they are involved in a crash rather than elevated risk of crash involvement—teenage drivers have the highest rates of involvement in crashes that result in the death of other people, such as their passengers, pedestrians, or drivers and passengers in other vehicles (Tefft, 2008).
Several studies have shown that the presence of passengers increases teenage drivers’ risk of involvement in severe or fatal crashes, especially when the passengers are also teenagers (Chen et al., 2000; Doherty, Andrey, & MacGregor, 1998; Preusser, Ferguson, & Williams, 1998; Rice, Peek-Asa, & Kraus, 2003; Tefft, Williams, & Grabowski, 2012). All of these studies also reported that this risk increases as the number of teenage passengers increases. Interestingly, the presence of young passengers seems to increase the risk of crashes that resulted in severe injury (Rice, Peek-Asa, & Kraus, 2003) or death (Chen et al., 2000; Tefft, Williams, & Grabowski, 2012) to a greater degree than it increases the risk of less severe crashes.
This elevated risk is believed to be attributable both to in-vehicle distractions and to risk taking related to characteristics associated with adolescent development (National Research Council, 1999; 2006). A study of police reports of fatal crashes that involved 16- year-old drivers in the state of California identified cases in which passengers urged the driver to perform dangerous behaviors, cases in which passengers had physically interfered with the driver (e.g., by grabbing the steering wheel), as well as cases in which it was evident that the passengers had distracted the driver (Williams, Preusser, & Ferguson, 1998). A recent study that used in-vehicle cameras to monitor a sample of teens for their first six months of licensed driving found that although passengers did not often actively urge the driver to take risks, drivers were more likely to speed, tailgate, or show off when they had multiple teenage passengers in the vehicle (Goodwin, Foss, & O’Brien, 2012), suggesting that it was the mere presence of the passengers that affected the driver’s behavior. Somewhat unexpectedly, in another study in which a different sample of newly- licensed teens was monitored using cameras and other in-vehicle data collection equipment, risky driving (as indicated by elevated g-force events, e.g., hard acceleration, braking, or swerving) was found to be less frequent in the presence of teen passengers (Simons-Morton et al., 2011).
In recent years, the predominant means by which jurisdictions have attempted to address the well-documented risks that young drivers face has been graduated driver licensing (GDL) systems. GDL systems seek to foster learning to drive under safe conditions by initially placing some restrictions on new drivers, and then relaxing the restrictions and granting more privileges as the young driver gains experience. Typically, a new driver first receives a learner’s permit, and is only allowed to drive with a parent or another licensed adult in the vehicle. After holding the learner’s permit for a certain amount of time, completing a specified amount of supervised driving practice, or both (specific requirements vary by state), the driver can receive an intermediate license (referred to in some states as a provisional license, a probationary license, or a junior operator’s license), which allows driving without an adult in the car, but only under certain conditions. During the intermediate stage of licensure, most states prohibit driving during certain late-night hours and place a limit on the number of young passengers (e.g., under age 21) that the driver is allowed to have in the car. When the driver has had the intermediate license for a certain length of time (e.g., 6 months) or reaches a certain age (e.g., 18), the driver “graduates” to a full license with no such restrictions. It is well-established that GDL has been effective in reducing the crash involvement rates of young drivers (Shope, 2007). Studies that have investigated the effect of passenger restrictions specifically have consistently reported that they have been effective in reducing the crash involvement of young drivers carrying passengers (Chaudhary, Williams, & Nissen, 2007; McCartt et al., 2010; Fell et al., 2011).
As of the end of the study period (December 31, 2010), 42 U.S. states and the District of Columbia had some form of passenger restriction as a part of their GDL program (Insurance Institute for Highway Safety [IIHS], 2012) (Appendix A). In addition, two states—Michigan and Pennsylvania—implemented passenger restrictions between the end of the study period and the publication date of this report. As Appendix A shows, there is substantial variation among states in the number of passengers that a driver with an intermediate license is allowed to carry, as well as in the duration of the passenger restriction.
The objective of this study was to document the proportion of fatal crashes of 16- and 17- year-old drivers in which passengers were present in relation to the age, sex, and number of passengers in the vehicle, and to examine the characteristics of these crashes in relation to specific combinations of passengers. In addition, summary data on the number of fatal crashes of 16- and 17-year-old drivers with various combinations of passengers are presented on a state-by-state basis to allow identification of targets of opportunity for improvement at the state level in the implementation, refinement, or enforcement of passenger restrictions as a part of each state’s overall strategy to reduce the number of teenage drivers involved in fatal motor vehicle crashes.
About the AAA Foundation for Traffic Safety
“Founded in 1947, the AAA Foundation in Washington, D.C. is a not-for-profit, publicly supported charitable research and education organization dedicated to saving lives by preventing traffic crashes and reducing injuries when crashes occur. Funding for this report was provided by voluntary contributions from AAA/CAA and their affiliated motor clubs, from individual members, from AAA-affiliated insurance companies, as well as from other organizations or sources.”