Young Driver Crash Rates and Iowa’s Passenger Restriction Waiver 17-SPR0-009

(2018) Young Driver Crash Rates and Iowa’s Passenger Restriction Waiver 17-SPR0-009.

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Abstract

Iowa is the only state in the US that gives parents the option to implement or waive a passenger restriction that limits the number of unrelated minor passengers to one for the first six months of licensure. The restriction does not apply to a driver’s sibling, step‐sibling, or a child who resides at the same household as the driver. The Iowa DOT indicated that approximately 90% of parents choose to waive the restriction during 2014, the first year the policy was in effect. This study analyzed crash rates for young drivers who were and were not subject to the passenger restriction in the first six months of intermediate licensure. Rates for the subsequent six months (i.e., after the passenger restriction has ended) were also analyzed. In addition, this study quantified the number of newly‐licensed drivers who were subject to the passenger restriction and their characteristics. Because many young drivers in Iowa obtain the optional minor school license (MSL), which allows teens as young as 14.5 years to drive to and from school and school‐related activities without a supervisor before obtaining his or her intermediate license, MSL and non‐MSL drivers were considered separately. While most parents waived the passenger restriction, the observed acceptance rate of 23% was higher than previously indicated. Even though the passenger restriction was associated with higher rather than lower crash rates among drivers who previously held a minor school license, the limitations associated with studying an optional policy do not permit conclusions to be drawn about the policy’s impact on the safety of young drivers and their passengers. Perhaps parents who perceived that their young driver was at higher risk of being involved in a crash were more likely to opt for the passenger restriction. It is conceivable that the crash rates would have been higher without the passenger restriction in place for those drivers. There is some evidence that parents who supported early driving for their teen drivers (i.e., with a MSL and/or licensure at age 16.0) were less likely to opt for the passenger restriction. However, on the whole, these data offer very little insight into the parents’ decision making process for opting or waiving the passenger restriction. Before any modification to the current policy is considered, steps should be taken to learn what factors parents consider when making their decision about the passenger restriction. What safety statistics, goals and objectives, traits of the teen driver, family needs, and aspects of the parent‐teen relationship are being weighed when parents decide whether to opt for or waive the restriction? Conducting a survey of parents would provide important data about how Iowa’s GDL passenger restriction is being applied and to inform any potential policy change or educational effort.