Driver Head Locations: Considerations for Head Restraint Design

Details

• Personal Author:
  Ebert SM ; Hallman JJ ; Jones MLH ; Park J ; Reed MP
• Description:
  Objective: U.S. FMVSS 202a requires that a vehicle head restraint lie within a specified distance (55 mm) from the physical headform on the head restraint measurement device (HRMD). Smaller values of this distance, known as backset, are frequently associated with improved protection against neck injury in rear impact. In some vehicles, small backsets are also associated with complaints of head restraint interference with drivers' preferred head positions. The objective of this study is to examine head/head restraint distances using data from a lab study of driving posture to provide guidance for safe and comfortable head restraint design. Methods: Head positions were measured for 88 U.S. drivers in a laboratory mockup using a seat from a mid-size sedan. The head restraint was removed to allow measurement of drivers' preferred head locations without interference from the head restraint. Rates of disaccommodation, defined as interference between predicted possible head restraint locations and drivers' preferred head locations, were analyzed at HRMD-referenced backsets of 25, 50, 75, and 100 mm measured at 22 degrees and 25 degrees seat back angles. Results: With HRMD-referenced backsets of 25 mm and 50 mm measured at 25 degrees, the head restraint intersected the preferred head locations of 17.9 and 5.2% of the drivers, respectively. An HRMD-referenced backset measured at 22 degrees produced larger accommodation rates than the same backset measured at 25 degrees. Conclusions: The reported distribution of occupant head positions and the resulting restrictions on comfortable head restraint position at various HRMD-referenced backsets and seat back angles help provide guidance for head restraint design. Knowing the actual mean driver-selected seat back angle for a particular vehicle seat and the model presented in this work, a manufacturer can choose a head restraint location that will have a high likelihood of complying with FMVSS backset requirements while also achieving minimal disaccommodation. The findings in this study support the flexibility in the current FMVSS 202a that permits testing at more upright seat back angles than the 25 degrees originally proposed. [Description provided by NIOSH]
• Subjects:
  Asbestos Minerals Mining Occupational Health Safety
• Keywords:
  Accidents Author Keywords: Backset Automobile Safety Disaccommodation Driver Drivers Equipment Testing Head Location Head Restraint Injury Prevention Motor Vehicles Posture Safety Equipment Seat Back Angle

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• ISSN:
  1538-9588
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Michigan ; OSHA Region 5 ; OSHA Region 6 ; Texas
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  19
• Issue:
  8
• NIOSHTIC Number:
  nn:20055555
• Citation:
  Traffic Inj Prev 2018 Nov; 19(8):825-831
• Contact Point Address:
  Jangwoon Park, Department of Engineering, Texas A&M University -- Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412
• Email:
  jangwoon.park@tamucc.edu
• Federal Fiscal Year:
  2019
• Performing Organization:
  University of Michigan, Ann Arbor
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Traffic Injury Prevention
• End Date:
  20280630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:053ec8456b81a61dcb0b54e88db6da96104b5ccc560634165436cdefb8d6d4952328d5c8c7fd723f6c01d4791eadbb166ec72f4af3f51eb12ad83d3341da0355
• Download URL:
  https://stacks.cdc.gov/view/cdc/213380/cdc_213380_DS1.pdf
• File Type:
  [PDF - 621.36 KB ]