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Upper-Extremity Postures and Activities in Naturalistic Driving

UMTRI-Sheila Ebert-Hamilton
University of Michigan - Ann Arbor-Matthew Reed
Published 2018-04-03 by SAE International in United States
Driver upper-extremity postures and activities were manually coded in 9856 video frames from 165 drivers in 100 vehicles that were instrumented with interior cameras as part of the Connected Vehicle Safety Pilot Model Deployment study. Drivers had left, right, and both hands on the steering wheel in 64%, 46%, and 28%, respectively, of frames in which the hand placements could be determined. The driver’s left elbow was in contact with the door or armrest in 18% of frames, and the driver’s right elbow was contacting the center console armrest in 29% of frames. Men were more likely than women to use both the left and right armrests. Women had approximately the same percentage of armrest use across vehicles, but men’s usage differed widely, suggesting that armrest design may influence whether people of different statures can use the armrests comfortably. Women were more likely to have a phone in their right hands than men, and women were twice as likely as men to be wearing sunglasses during trips taken in daylight hours.
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Development of a Vehicle-Based Experimental Platform for Quantifying Passenger Motion Sickness during Test Track Operations

University of Michigan - Ann Arbor-Monica Lynn Haumann Jones, Kathleen Sienko, Sheila Ebert-Hamilton, Catherine Kinnaird, Carl Miller, Brian Lin, Byoung-Keon Park, John Sullivan, Matthew Reed, James Sayer
Published 2018-04-03 by SAE International in United States
Motion sickness in road vehicles may become an increasingly important problem as automation transforms drivers into passengers. Motion sickness could be mitigated through control of the vehicle motion dynamics, design of the interior environment, and other interventions. However, a lack of a definitive etiology of motion sickness challenges the design of automated vehicles (AVs) to address motion sickness susceptibility effectively. Few motion sickness studies have been conducted in naturalistic road-vehicle environments; instead, most research has been performed in driving simulators or on motion platforms that produce prescribed motion profiles. To address this gap, a vehicle-based experimental platform using a midsize sedan was developed to quantify motion sickness in road vehicles. A scripted, continuous drive consisting of a series of frequent 90-degree turns, braking, and lane changes were conducted on a closed track. The route was selected to be representative of naturalistic urban driving conditions and parameterized in terms of lateral and longitudinal acceleration intensities likely to produce motion sickness. Vehicle instrumentation included simultaneous measure of vehicle acceleration, passenger head kinematics, self-reported motion sickness ratings and…
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Effects of Seat and Sitter Dimensions on Pressure Distribution in Automotive Seats

Univ of Michigan - Ann Arbor-Monica Lynn Haumann Jones, Jangwoon Park, Sheila Ebert-Hamilton, K. Han Kim, Matthew P. Reed
Published 2017-03-28 by SAE International in United States
Seat fit is characterized by the spatial relationship between the seat and the vehicle occupant’s body. Seat surface pressure distribution is one of the best available quantitative measures of this relationship. However, the relationships between sitter attributes, pressure, and seat fit have not been well established. The objective of this study is to model seat pressure distribution as a function of the dimensions of the seat and the occupant’s body. A laboratory study was conducted using 12 production driver seats from passenger vehicles and light trucks. Thirty-eight men and women sat in each seat in a driving mockup. Seat surface pressure distribution was measured on the seatback and cushion. Relevant anthropometric dimensions were recorded for each participant and standardized dimensions based on SAE J2732 (2008) were acquired for each test seat. Regression models were effective in predicting characteristics of pressure distribution from the anthropometric variables and SAE J2732 dimensions. The resulting models may be useful to evaluate virtual fit simulations of the interaction between the seat and sitter.
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Evaluation of the Seat Index Point Tool for Military Seats

SAE International Journal of Commercial Vehicles

UMTRI-Sheila Ebert-Hamilton
University of Michigan-Matthew Reed
  • Journal Article
  • 2016-01-0309
Published 2016-04-05 by SAE International in United States
This study evaluated the ISO 5353 Seat Index Point Tool (SIPT) as an alternative to the SAE J826 H-point manikin for measuring military seats. A tool was fabricated based on the ISO specification and a custom back-angle measurement probe was designed and fitted to the SIPT. Comparisons between the two tools in a wide range of seating conditions showed that the mean SIP location was 5 mm aft of the H-point, with a standard deviation of 7.8 mm. Vertical location was not significantly different between the two tools (mean - 0.7 mm, sd 4.0 mm). A high correlation (r=0.9) was observed between the back angle measurements from the two tools. The SIPT was slightly more repeatable across installations and installers than the J826 manikin, with most of the discrepancy arising from situations with flat seat cushion angles and either unusually upright or reclined back angles that caused the J826 manikin to be unstable. The investigators who performed the measurements indicated that the SIPT was easier to use. The data show that the SIPT is a…
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Statistical Modeling of Automotive Seat Shapes

University of Michigan-K. Han Kim, Sheila Ebert-Hamilton, Matthew Reed
Published 2016-04-05 by SAE International in United States
Automotive seats are commonly described by one-dimensional measurements, including those documented in SAE J2732. However, 1-D measurements provide minimal information on seat shape. The goal of this work was to develop a statistical framework to analyze and model the surface shapes of seats by using techniques similar to those that have been used for modeling human body shapes. The 3-D contour of twelve driver seats of a pickup truck and sedans were scanned and aligned, and 408 landmarks were identified using a semi-automatic process. A template mesh of 18,306 vertices was morphed to match the scan at the landmark positions, and the remaining nodes were automatically adjusted to match the scanned surface. A principal component (PC) analysis was performed on the resulting homologous meshes. Each seat was uniquely represented by a set of PC scores; 10 PC scores explained 95% of the total variance. This new shape description has many applications. For instance, seats can be classified and grouped, and the distinctive features and dimensions that characterize each group can be identified. Seats can be…
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Development of an Automatic Seat-Dimension Extraction System

UMTRI-Jangwoon Park, Sheila Ebert-Hamilton, K. Han Kim, Monica Jones, Byoung-Keon Park, Matthew Reed
Published 2016-04-05 by SAE International in United States
This paper reports on the development and validation of an automated seat-dimension extraction system that can efficiently and reliably measure SAE J2732 (2008) seat dimensions from 3D seat scan data. The automated dimension-extraction process consists of four phases: (1) import 3D seat scan data along with seat reference information such as H-point location, back and cushion angles, (2) calculate centerline and lateral cross-section lines on the imported 3D seat scan data, (3) identify landmarks on the centerline and cross-section lines based on the SAE J2732 definitions, and (4) measure seat-dimensions using the identified landmarks. To validate the automated seat measurements, manually measured dimensions in a computer-aided-design (CAD) environment and automatically extracted ones in the current system were compared in terms of mean discrepancy and intra- and inter-observer standard deviations (SD). The automatically extracted seat-dimensions were more repeatable than those obtained with manual measurement in CAD. Automatically extracted seat-dimensions using the current system would be useful for evaluating or benchmarking seats for which design data is lacking
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A Pilot Study of Occupant Accommodation and Seat Belt Fit for Law Enforcement Officers

University of Michigan Transportation Research Institute-Monica Lynn Haumann Jones, Sheila Ebert-Hamilton, Matthew Reed
Published 2016-04-05 by SAE International in United States
Law enforcement officers (LEO) make extensive use of vehicles to perform their jobs, often spending large portions of a shift behind the wheel. Few LEO vehicles are purpose-built; the vast majority are modified civilian vehicles. Data from the field indicate that LEO suffer from relatively high levels musculoskeletal injury that may be due in part to poor accommodation provided by their vehicles. LEO are also exposed to elevated crash injury risk, which may be exacerbated by a compromise in the performance of the occupant restraint systems due to body-borne equipment. A pilot study was conducted to demonstrate the application of three-dimensional anthropometric scanning and measurement technology to address critical concerns related to vehicle design. Detailed posture and belt fit data were gathered from five law enforcement officers as they sat in the patrol vehicles that they regularly used and in a mockup of a mid-sized vehicle. The size and shape of the officers was measured with and without police uniform and duty belt using standard anthropometry techniques and a whole-body laser scanner. The new methods…
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Distribution of Belt Anchorage Locations in the Second Row of Passenger Cars and Light Trucks

SAE International Journal of Transportation Safety

UMTRI-Sheila Ebert-Hamilton
Univ. of Michigan-Matthew P. Reed
  • Journal Article
  • 2013-01-1157
Published 2013-04-08 by SAE International in United States
Seat belt anchorage locations have a strong effect on occupant protection. Federal Motor Vehicle Safety Standard (FMVSS) 210 specifies requirements for the layout of the anchorages relative to the seating reference point and seat back angle established by the SAE J826 H-point manikin. Sled testing and computational simulation has established that belt anchorage locations have a strong effect on occupant kinematics, particularly for child occupants using the belt as their primary restraint. As part of a larger study of vehicle geometry, the locations of the anchorage points in the second-row, outboard seating positions of 83 passenger cars and light trucks with a median model year of 2005 were measured. The lower anchorage locations spanned the entire range of lap belt angles permissible under FMVSS 210 and the upper anchorages (D-ring locations) were distributed widely as well. Combined with the findings from concurrent research on the effects of belt geometry, these results suggest that occupant kinematics in frontal impact can be expected to differ widely across vehicles due to differences in belt geometry.
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