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Accession Number PB2013-103568
Title LATCH Usability in Vehicles.
Publication Date Apr 2012
Media Count 158p
Personal Author C. A. C. Flanagan J. L. Moore K. D. Klinich M. A. Manary
Abstract This project investigated the usability of Lower Anchors and Tethers for CHildren (LATCH) hardware by measuring LATCH implementations in 98 2011 or 2010 model-year vehicles. ISO and SAE LATCH usability rating systems were used to assess all vehicles using data from the second row left position. Child restraint/vehicle interaction was assessed using both ISO and NHTSA proposed procedures. Volunteer testing was performed with 36 subjects on 12 different vehicles using 3 different child restraints, with each subject performing 8 child restraint installations. The results from the vehicle survey indicate that most vehicle manufacturers provide LATCH hardware at only the minimum number of locations required by FMVSS 225. Only 7 vehicles had three sets of LATCH hardware in the second row, while most of the remaining 91 vehicles were only equipped with LATCH in each outboard position and a tether anchor in the center position. In the 21 vehicles with a third row, four had no tether anchors and 11 had no lower anchors in the third row. The SAE child restraint fixture could not be installed in 27 vehicles, although head restraint interference was the cause of interference in only one vehicle. Fifty-nine vehicles met the SAE recommended lower attachment force of 75 N (16.9 lb) or less, while 15 vehicles required forces from 2 to 8 times this value. Only 2 vehicles met SAE recommendations for clearance angle of at least 75 degrees around the lower anchors. The depth of the lower anchors relative to the bight is less than 2 cm in 28 vehicles, 2-4 cm in 34 vehicles, and greater than 4 cm in 36 vehicles. The most common location for the tether anchor is the seatback (42) and package shelf (35). The lower anchors are marked in 77 vehicles, while the tether anchors are marked in 68 vehicles. Only Ford products clearly specify weight ranges for use of LATCH hardware in their manuals. Many vehicle manuals are not clear on how the head restraint should be positioned during child restraint installation. ISO ratings of vehicle LATCH usability ranged from 41% to 78%, while vehicles assessed using the SAE draft recommended practice met between 2 and all 10 of the recommendations. There was a slight correlation between vehicles meeting SAE recommended practices and ISO usability ratings. Twenty vehicles with a range of vehicle features were assessed using the ISO vehicle/child restraint form and 7 child restraints; ISO vehicle/child restraint interaction scores ranged from 14% to 86%.
Keywords Child restraint systems
Child safety seats
Implementation
Installation
Lower Anchors and Tethers for CHildren(LATCH) hardware
Measurement
Occupant protection
Rating system
Safety seats
Surveys
Usability
Vehicles
Volunteers

 
Source Agency University of Michigan Transportation Research Institute
NTIS Subject Category 85D - Transportation Safety
85H - Road Transportation
91B - Transportation & Traffic Planning
43G - Transportation
Corporate Author Michigan Univ., Ann Arbor. Transportation Research Inst.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1309
Contract Number N/A

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