Investigation of Crash Consequences for Common Child Restraint Misuse

Estimates of child restraint misuse rates in the United States range from 49 to 95 percent, but not all misuse modes have similar consequences in terms of restraint effectiveness. A series of laboratory sled tests was conducted to determine the effects of common misuses and combinations of misuses, including loose harness, loose installation, incorrect installation angle, incorrect belt path, loose/no tether, and incorrect harness clip usage. Three commercial convertible child restraint models loaded with the Hybrid III 3YO ATD and secured by either LATCH belt or lap seat belt were tested in rear-facing and forward-facing configurations on a modified FMVSS 213 bench. The response variables included ATD accelerations, excursions, and restraint kinematics. Belt/LATCH loads, tether loads, ATD kinematics, and restraint structural response data were also documented. A fractional factorial test design on eight factors was used to define an initial series of 32 tests. The analysis of that data determined the selection of conditions for the remaining 20 tests to focus on factors and interactions of high interest and significance. In the rear-facing condition, misrouting the LATCH belt or seatbelt through the incorrect belt path was the only misuse that significantly affected outcomes of interest and was associated with high levels of undesirable CRS rotation. In forward-facing tests, loose installation and tether misuse had large adverse effects on three out of four key response variables. Because the results show that a rear-facing installation is more resistant to user error, they also provide support for extended rear-facing restraint use. The study provides strong evidence for prioritizing tight restraint installation and proper tether use for forward-facing restraints. In particular, use of the tether helped to reduce the adverse effects of loose installation or loose harness.

• Record URL:
  https://rosap.ntl.bts.gov/view/dot/56575
• Corporate Authors:

  University of Michigan Transportation Research Institute

  2901 Baxter Road
  Ann Arbor, Michigan  United States  48109

  National Highway Traffic Safety Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Manary, Miriam
  • Klinich, Kathleen
  • Reed, Matthew P
  • Flannagan, Carol A C
  • Orton, Nichole R
• Publication Date: 2021-7

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final
• Features: Figures; Photos; References; Tables;
• Pagination: 42p

Subject/Index Terms

• TRT Terms: Child restraint systems; Human error; Sled tests; Traffic crashes
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 01778454
• Record Type: Publication
• Report/Paper Numbers: DOT HS 813 1 00
• Files: HSL, NTL, TRIS, ATRI, USDOT
• Created Date: Jul 30 2021 12:35PM