Investigation of Potential Design and Performance Criteria for Booster Seats Through Volunteer and Dynamic Testing

Technical Report FinalThe purpose of this research was to explore candidate booster performance metrics that have the potential to identify less effective booster systems, since current FMVSS No. 213 booster performance requirements can be met without a booster. A combination of volunteer testing of belt fit and posture along with dynamic sled tests of booster seats was employed to achieve the project goals. Posture and belt fit were measured in 24 child volunteers 4 to 12 years old. Children were measured in three vehicles and three laboratory seating conditions selected to provide cushion lengths and belt geometries representing the range found in late model vehicle rear seats. Six different booster seats, as well as the no-booster condition, were evaluated. Test conditions were also evaluated using 6YO, 10YO, and small female anthropomorphic test devices (ATDs). Posture differences between children and ATDs were greater in the no-booster condition and the two lower backless boosters compared to the four boosters that raised the occupant by 75 mm or more, but the differences were not large enough to warrant recommendation of an alternate seating procedure. The shoulder belt tended to be closer to the ATD necks than those of child volunteers; the lap belt was always further below the ATD ASIS than the volunteer’s belt. To provide a more realistic test environment, dynamic testing was performed using a surrogate seat belt retractor on the most recent preliminary design update for the FMVSS No. 213 seat assembly. Eleven booster products were evaluated, as well as the no-booster condition, with six tests performed using the Hybrid III 10YO and 33 tests run with the Hybrid III 6YO. Possible metrics associated with good ATD kinematics (no submarining or rollout) were the difference between knee and head excursion, maximum torso angle, as well as lumbar MomentZ and ForceY. Tests with the surrogate retractor were as repeatable as testing with current FMVSS No. 213 conditions.National Highway Traffic Safety Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/167692/2/UMTRI-2020-6.pdfDescription of UMTRI-2020-6.pdf : Technical Report Fina

Biomechanics of pedestrian injuries related to lower extremity injury assessment tools: a review of the literature and analysis of pedestrian crash database

Notes: "September 2003."Notes: Final reportNotes: Includes bibliographical references (p. 87-91)Alliance of Automobile Manufacturers, Southfield, Mich.http://deepblue.lib.umich.edu/bitstream/2027.42/1535/2/97318.0001.001.pd

Seated anthropometry during pregnancy: final report

General Motors Corporation, Warren, Mich.National Highway Traffic Safety Administration, Washington, D.C.http://deepblue.lib.umich.edu/bitstream/2027.42/1287/2/92588.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/1287/4/92588-color.pd

Investigations of crashes involving pregnant occupants

General Motors Corporation, Warren, Mich.http://deepblue.lib.umich.edu/bitstream/2027.42/1294/2/94053.0001.001.pd

Feasibility of center LATCH

Period Covered: October 2012-July 2013This paper explores the geometric feasibility of installing dedicated lower anchors in the center rear seating positions of vehicles. Analysis was based on a previous research study in which the lateral spacing of seat belt and LATCH lower anchorages were measured in 85 model year 2010-2011 vehicles. The goal of this study was to determine how many vehicles would have the physical space to incorporate a third set of dedicated lower anchors in the center seating position for child restraint installation. Usability of all of the lower anchors, as well as the seat belts, was also considered. To begin, nine vehicles that currently have dedicated lower anchors in the center position were reviewed. The distances between all seat belt anchors and lower anchors across the vehicle sample were also analyzed to identify spacings that are currently feasible in production. The arrangement of seat belt and lower anchor hardware across the rear seat was also reviewed with respect to usability. Based on these analyses, a lateral distance between the outboard webbing and outboard lower anchor of 75 to 100 mm is common. The suggested minimum distance between lower anchors and seat belt hardware is 25 mm. Based on these dimensions, vehicles with 710 mm or more between the outboard lower anchor centerlines (OBLACL) should have sufficient space to provide three sets of usable, dedicated lower anchors in the right, center, and left seating positions. Providing the highest level of usability with regard to use of seat belt or LATCH hardware in adjacent seating positions would be achieved by placing each pair of lower anchors between the webbing and buckle hardware for the seating position. If the OBLACL is less than 710 mm, an improvised center LATCH position (permitting use of the inboard lower anchors from the outboard seating positions to secure a child restraint in the center seating position) may be feasible. The maximum spacing of this improvised center LATCH position would be 480 mm. If a vehicle allowed an improvised center LATCH position, placing the inboard lower anchor between the outboard buckle and nearest center seat belt hardware would maximize usability of the seat belt in the outboard seating position and lower anchors in the center seating position.National Highway Traffic Safety Administration U.S. Department of Transportationhttp://deepblue.lib.umich.edu/bitstream/2027.42/111831/1/103191.pd

Tether Anchors in Pickup Trucks: Assessing Usability, Labeling and Performance

Technical Report FinalThis project investigated factors relating to tether use and misuse in pickup trucks and evaluated four interventions designed to educate consumers on proper use. The dynamic performance of four tether locations was also evaluated. Volunteer testing was performed with 24 subjects on 4 different pickup trucks using 2 forward-facing child restraints (Britax Marathon G4.1 and the Evenflo Triumph), with each subject performing 8 child restraint installations on the set of four vehicles. Pickup trucks were selected to represent four different implementations of tether anchors in pickup trucks: Chevy Silverado (plastic wire loop routers), Dodge Ram (webbing routers), Nissan Frontier (back wall anchor), and Toyota Tundra (webbing routers plus metal anchor). Interventions included a diagram label, QR code linked to video instruction, coordinating (i.e., low contrast with interior trim) text label, and contrasting-color text tag. Subjects used the tether in 93% of trials. However, tether use was completely correct in only 9% of trials. The installation was considered functional if the subject attached the tether to a tether anchor and had a tight installation (ignoring routing and head restraint position); 28% of subjects achieved a functional installation. The most common error was attaching the tether anchor to the anchor/router directly behind the child restraint rather than placing it through the router and attaching it to the anchor in the adjacent seating position. The Nissan Frontier, with the anchor located behind the seatback, had the highest rate of correct installations but also had the highest rate of attaching to components other than a tether anchor (seat adjustor, child restraint hardware, head restraint). None of the interventions had a significant effect on correct installation; not a single subject scanned the QR code to access the video instructions. The most successful subjects spent extensive time reviewing the vehicle manuals. Results indicate that current implementations of tether anchors in pickup trucks are not intuitive and alternate designs should be explored. A set of impact tests was run using the proposed FMVSS No. 213 bench to evaluate the dynamic performance of the different tether anchor locations used in the subject testing, with and without 50 mm of slack. A tether anchor location simulating a roof-mounted location above the rear window of a pickup was also included in the matrix. Slack had a greater effect on head excursion compared to tether anchor location. Tether anchors located on the seatback, filler panel, or at an adjacent seating position had the lowest head excursions, followed by an anchor located above the window, followed by no tether anchor. Future research should involve testing performance of a tether anchor located above the window after being placed through a tether routerInsurance Institute for Highway Safetyhttps://deepblue.lib.umich.edu/bitstream/2027.42/156027/1/UMTRI-2016-30.pdfDescription of UMTRI-2016-30.pdf : Technical Report Fina

Driver distraction from cell phone use and potential for self-limiting behavior

This project consists of three parts. The first is a review of the literature on driver distraction that primarily focuses on cell phone use. The second two parts involve analysis of an existing field operational test (FOT) database to examine: 1) self-limiting behavior on the part of drivers who use cell phones, and 2) eye glance patterns for drivers involved in cell phone conversations and visual-manual tasks (e.g., texting) as compared to no-task baseline driving. The literature review discusses the apparent contradiction between results of case-crossover and simulator studies that show increases in instantaneous risk due to talking on a cell phone and results of crash-data analyses that show no substantial increase in crashes associated with increases in cell phone use in vehicles. The first data analysis shows some evidence of self-limiting behavior in cell phone conversations. Drivers initiate calls when on slower roads and at slower speeds, often when stopped. However, they call more at night, which is a higher-risk time to drive. The second analysis showed that eye glances when talking on the phone are fixated on the road for longer periods of time than in baseline driving. In contrast, on-road eye glances when engaged in a visual-manual (VM) task are short and numerous. Eye glances on and off the road are about equal in length, and the average total off-road gaze time for a five-second interval is about 2.8 secs, or 57% of the time. Average off-road gaze time out of five seconds in baseline driving is about 0.8 sec, or 16% of the time. Results show the differences in distraction mechanism between cell-phone conversations and texting. Ramifications for potential interventions are discussed.State Farm Insurancehttp://deepblue.lib.umich.edu/bitstream/2027.42/108381/1/103022.pd

Effect of realistic vehicle seats, cushion length, and lap belt geometry on child ATD kinematics

This series of sled tests examined the effect of using real vehicle seats on child ATD performance. Cushion length was varied from production length of 450 mm to a shorter length of 350 mm. Lap belt geometry was set to rear, mid, and forward anchorage locations that span the range of allowable lap belt angles found in real vehicles. Six tests each were performed with the standard Hybrid III 6YO and 10YO ATDs. One additional test was performed using a booster seat with the 6YO. An updated version of the UMTRI seating procedure was used to position the ATDs that positions the ATD hips further forward with longer seat cushions to reflect the effect of cushion length on posture that has been measured with child volunteers. ATD kinematics were evaluated using peak head excursion, peak knee excursion, the difference between peak head and peak knee excursion, and the minimum torso angle. Shortening the seat cushion improved kinematic outcomes, particularly for the 10YO. Lap belt geometry had a greater effect on kinematics with the longer cushion length, with mid and forward belt geometries producing better kinematics than the rearward belt geometry. The worst kinematics for both ATDs occurred with the long cushion length and rearward lap belt geometry. The improvements in kinematics from shorter cushion length or more forward belt geometry are smaller than those provided by a booster seat. The results show potential benefits in occupant protection from shortening cushion length, particularly for children the size of the 10YO ATD.National Highway Traffic Safety Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/90972/1/102859.pd

Injury patterns in motor-vehicle crashes in the United States: 1998 - 2014

The NASS-CDS database for years 1998-2014 was analyzed to examine trends in injury patterns. To account for changes in data collection for years 2009 and later, most analyses focused on occupants in vehicles newer than 10 years relative to the given crash year. However, for analysis of trends by crash year, the number of occupants injured in older vehicle was estimated. The number of occupants with AIS2+ or AIS3+ injuries was assessed by main crash type (rollover, frontal, rear, near-side, and far-side) and AIS body region (head, face, neck, thorax, spine, abdomen, upper extremity and lower extremity). Risk of AIS2+ or AIS3+ injury was also calculated. Dependent variables include occupant age, BMI, gender, occupant seating position, and restraint; vehicle type and model year; plus crash year. Additional analyses were performed to determine if injury patterns varied within body region. Overall trends in injury indicate a substantial drop in the total number of injuries since 1999. Risk has dropped consistently for near- and far-side crashes, but not for rollovers, frontal, or rear impacts. For AIS3+ injured occupants, the 16% of occupants who are unbelted make up between 45-55% of injured occupants in all crash types except for near-side. Rear occupants have a 1.7 times greater risk of AIS2+ injury in far-side impacts and 2.2 times greater risk in rear impacts compared to front seat occupants, but front occupants have 1.5 times greater risk than rear occupants in frontal crashes. The risk of AIS2+ and AIS3+ injury to all body regions generally increase with age. The proportion of AIS2+ and AIS3+ injured occupants in rollovers decreases with age. In frontal, near-side, and far-side crashes, occupants with AIS2+ injury aged 66 and greater make up a higher proportion of the injured occupants compared to their involvement crashes. Risk of AIS3+ injury is highest in pickup trucks for frontal crashes, near-side and rear crashes and in passenger cars for far-side and rollovers. Risk of AIS2+ and AIS3+ injury is highest in pickup trucks for all AIS body regions. Risk of AIS3+ injury to the pelvis and femur have dropped substantially since vehicle model years 1999-2004.National Highway Traffic Safety Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/135950/1/103253.pdfDescription of 103253.pdf : Final repor

LATCH usability in vehicles

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%. Based on these interaction scores, the Cosco Alpha Omega, the Chicco KeyFit, and Evenflo Maestro were used with a subset of 12 vehicles to perform volunteer testing and assess the quality of subject installations. No vehicle factors predicted tether use or correct use of tether. However, the correct use of lower anchors was associated with a lower anchor clearance angle greater than 54°, an attachment force of 40 lb or less, and lower anchor depth within the bight of less than 2 cm. Correct lower anchor use also had 3.3 times higher odds of tight installation compared to incorrect use.Insurance Institute for Highway Safetyhttp://deepblue.lib.umich.edu/bitstream/2027.42/90856/1/102854.pd