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Objective: Identify factors that impact parents' decisions about allowing an unaccompanied child to ride in an autonomous vehicle (AV).Background: AVs are being tested in several U.S. cities and on highways in multiple states. Meanwhile, suburban parents are using ridesharing services to shuttle children from school to extracurricular activities. Parents may soon be able to hire AVs to transport children.Method: Nineteen parents of 8- to 16-year-old children, and some of their children, rode in a driving simulator in autonomous mode, then were interviewed. Parents also participated in focus groups. Topics included minimum age for solo child passengers, types of trips unaccompanied children might take, and vehicle features needed to support child passengers.Results: Parents would require two-way audio communication and prefer video feeds of vehicle interiors, seatbelt checks, automatic locking, secure passenger identification, and remote access to vehicle information. Parents cited convenience as the greatest benefit and fear that AVs could not protect passengers during unplanned trip interruptions as their greatest concern.Conclusion: Manufacturers have an opportunity to design family-friendly AVs from the outset, rather than retrofit them to be safe for child passengers. More research, especially usability studies where families interact with technology prototypes, is needed to understand how AV design impacts child passengers.Application: Potential applications of this research include not only designing vehicles that can be used to safely transport children, seniors who no longer drive, and individuals with disabilities but also developing regulations, policies, and societal infrastructure to support safe child transport via AVs. [ABSTRACT FROM AUTHOR]

Objective: Emergency maneuvers such as evasive swerving often precede a crash. These events are typically low-acceleration, time-extended events where the inertial forces have the potential to cause changes to the occupant's initial state (initial posture, position, muscle tension). The objective of this study was to systematically quantify the kinematics of pediatric and adult human volunteers during simulated pre-crash evasive swerving maneuvers and evaluate the effect of age and two vehicle-based countermeasures.Methods: A novel laboratory device was designed to expose subjects to non-injurious loading conditions that mimic real-world evasive swerving events. A four-cycle oscillatory lateral pulse with a maximum acceleration of 0.72 g (0.53 g for the first lateral movement in the first cycle) was applied. Forty seat belt restrained subjects across four age groups - 9-11 years (n = 10), 12-14 years (n = 10), 15-17 years (n = 10) and 18-40 years (n = 10) - were exposed to a series of test conditions (baseline, pre-pretensioned seat belt, sculpted vehicle seat with and without inflated torso bolsters) while their kinematics were captured using 3 D motion capture and muscle activity was recorded. Reaction loads were collected from the shoulder belt and footrest. Data are presented for the first cycle only.Results: Pre-pretensioning the shoulder belt before the onset of acceleration had the greatest restraining effect on the head and trunk for all age groups. In the pre-pretensioning trials, compared to baseline, subjects exhibited 34% and 33% less head excursion, into and out of the shoulder belt respectively. Similar reductions were observed with pre-pretensioning for trunk excursion (45% and 53% reductions, in and out of the belt respectively). Inflating seat torso bolsters reduced lateral kinematics relative to baseline but to a lesser extent than the pre-pretensioner (Head Out of belt: 11%; Head Into Belt: 32% and Trunk Out of Belt: 15%; Trunk Into Belt: 27%). Although there was no overall effect of age on the magnitude of lateral displacement, different age groups employed various neuromuscular strategies to control their kinematics.Conclusion: A pre-pretensioner was an effective vehicle countermeasure during evasive swerving maneuvers as it substantially reduced lateral head and trunk displacement for all age groups. Providing lateral restraint via a sculpted vehicle seat was less effective as the geometry of the torso bolsters when inflated did not provide substantial lateral support. [ABSTRACT FROM AUTHOR]

Designing motor vehicle safety systems requires knowledge of whole body kinematics during dynamic loading for occupants of varying size and age, often obtained from sled tests with postmortem human subjects and human volunteers. Recently, we reported pediatric and adult responses in low-speed (<4 g) automotive-like impacts, noting reductions in maximum excursion with increasing age. Since the time-based trajectory shape is also relevant for restraint design, this study quantified the time-series trajectories using basis splines and developed a statistical model for predicting trajectories as a function of body dimension or age. Previously collected trajectories of the head, spine, and pelvis were modeled using cubic basis splines with eight control points. A principal component analysis was conducted on the control points and related to erect seated height using a linear regression model. The resulting statistical model quantified how trajectories became shorter and flatter with increasing body size, corresponding to the validation data-set. Trajectories were then predicted for erect seated heights corresponding to pediatric and adult anthropomorphic test devices (ATDs), thus generating performance criteria for the ATDs based on human response. This statistical model can be used to predict trajectories for a subject of specified anthropometry and utilized in subject-specific computational models of occupant response. [ABSTRACT FROM PUBLISHER]