Principal Investigator: Julie Mansfield, PhD, The Ohio State University

WHAT WAS THE PURPOSE OF THIS PROJECT?

Infant CRS can be installed without the base using two different methods: 1) using primarily the lap belt and routing the shoulder belt directly up to the retractor known as the traditional belt path or 2) using the lap belt and additionally wrapping the shoulder belt around the back of the infant carrier, known as the European belt path. Some CRS models require or prefer a certain installation method, while others allow both. Little is known about whether caregivers can accurately complete each of these installation options and whether these CRS fit into US vehicles.

HOW WAS THE RESEARCH CONDUCTED?

There were three different aims and methods for this project. For Aim 1, we looked at compatibility by comparing key measurements from a convenience sample of 30 vehicles to corresponding dimensions of 10 CRS. For Aim 2, we studied consumer usability by recruiting 30 caregivers from the community to install CRS using each method and tracked their errors. For Aim 3, we analyzed the stability of each installation method (that is, its ability to stay upright without lateral or rotational shifting) during real-world driving. Misuse conditions were compared to correct installations.

WHAT WERE THE FINDINGS AND WAS ANYTHING SURPRISING?

In terms of compatibility, the primary focus was confirming that the height of the seat belt buckle fit underneath the infant CRS belt guide and ensuring the seat belt was long enough to route around the back of the CRS. We found generally good compatibility across the field. For Aim 2, overall misuse rates were similar to those reported in child safety literature. However, caregivers had fewer major errors using the European belt path (43.3%) compared to the traditional belt path (80.0%). This was surprising because the European belt path has a few additional steps, which we thought may lead to more errors. Interestingly, 100% of the installations completed using the European method had the seat belt locked correctly. This is because the belt needed to be extended to nearly its maximum length to fit around the European belt path. Additionally, most users recognized that the European belt path provided a more stable installation and felt it was safer than the traditional belt path. For Aim 3, the European belt path appeared to create a more stable installation compared to the traditional method, especially when misuses were present.

HOW ARE THESE RESULTS APPLICABLE TO INDUSTRY MEMBERS?

We hope that the industry sponsors can use this information to help prioritize which installation method is recommended to caregivers. Considering all three aims, there is evidence that the European belt path is a feasible and practical option for caregivers that provides more stability.

IAB Mentors

Michael Block, Consumer Reports; Emily Thomas, Consumer Reports; Suzanne Johansson, General Motors Holdings, LLC; Mark LaPlante, Graco Children’s Products Inc.; Marianne LeClaire, Graco Children’s Products Inc.; Kelly Seagren, Graco Children’s Products Inc.; Joseph Webb, Graco Children’s Products Inc.; Emily Burton, American Honda Motor Co., Inc.; Steve Gerhart, Nuna Baby; Anita Sabapathy, UPPAbaby; Uwe Meissner, Technical Advisor