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Seatbelt Entanglement: Field Analysis, Countermeasure Development, and Subject Evaluation of Devices Intended to Reduce Risk

UMTRI-Kathleen DeSantis Klinich, Sheila Ebert, Laura Malik, Miriam A. Manary
Tool Inc.-Jason Sidman, Bill Liteplo
Published 2019-04-02 by SAE International in United States
Since 2000, over 200 rear seat occupants have become entangled in the seatbelt when they inadvertently switched it from emergency locking mode (ELR) to automatic locking mode (ALR). Since a method is needed to lock the seatbelt when installing child restraint systems (CRS), the National Highway Traffic Safety Administration (NHTSA) commissioned tool, inc. to develop prototype devices that could reduce the risk of seatbelt entanglement resulting from the lockability requirement. A field analysis of entanglement incidents was first conducted to inform countermeasure design. Prototype devices were developed and evaluated through testing with volunteer subjects in comparison to standard seatbelt systems by assessing how different designs would be used to install CRS, the quality of the resulting installations, how users would disentangle a trapped child surrogate, as well as to identify volunteer experience when using the belts themselves. Four prototype devices were evaluated in two phases of testing conducted at the UMTRI. All four prototype devices had shorter disentanglement times than trials with the standard seatbelt, but there was not a statistically significant difference between the…
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Development of an Automated Seat Dimension Evaluation System

UMTRI-Byoung-Keon Park
Hyundai Motor Company-Baekhee Lee, Minhyuk Kwak, Yungsik Kim
Published 2019-04-02 by SAE International in United States
The dimensions of an automobile seat are important factors affecting a driver’s seating comfort, fit, and satisfaction. In this regard, seat engineers put forth tremendous efforts to evaluate the dimensions of a product seat until the dimensions are consistent with the design reference in a computer aided design (CAD). However, the existing evaluation process is heavily reliant on seat engineers’ manual tasks which are highly repetitive, labor intensive, and time-demanding tasks. The objective of this study is to develop an automated system that can efficiently and accurately evaluate seat products by comparing estimated seat dimensions from a CAD model or a 3D scan model. By using the developed system, the evaluation time for comparing 18 seat dimensions on CAD and scan models has been substantially reduced to less than one minute, which is 99% time saving compared to two hours in the manual process. In addition, the seat dimensions can be more repeatedly measured than manual measurements by using developed computer-based algorithms. In conclusion, the developed system is particularly useful for quantitatively controlling the quality…
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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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In-Vehicle Occupant Head Tracking Using aLow-Cost Depth Camera

UMTRI-Byoung-Keon Daniel Park
Toyota Motor North America Inc.-Jason Hallman, Rini Sherony
Published 2018-04-03 by SAE International in United States
Analyzing dynamic postures of vehicle occupants in various situations is valuable for improving occupant accommodation and safety. Accurate tracking of an occupant’s head is of particular importance because the head has a large range of motion, controls gaze, and may require special protection in dynamic events including crashes. Previous vehicle occupant posture studies have primarily used marker-based optical motion capture systems or multiple video cameras for tracking facial features or markers on the head. However, the former approach has limitations for collecting on-road data, and the latter is limited by requiring intensive manual postprocessing to obtain suitable accuracy. This paper presents an automated on-road head tracking method using a single Microsoft Kinect V2 sensor, which uses a time-of-flight measurement principle to obtain a 3D point cloud representing objects in the scene at approximately 30 Hz. Vehicle passenger motions were recorded during hard braking and rapid lane changes. The dynamic head orientation and location data were obtained by fitting a subject-specific 3d head model to the depth data from each frame. Results were validated using a marker-based…
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Characterizing Vehicle Occupant Body Dimensions and Postures Using a Statistical Body Shape Model

UMTRI-Byoung-Keon Daniel Park
University of Michigan-Matthew P. Reed
Published 2017-03-28 by SAE International in United States
Reliable, accurate data on vehicle occupant characteristics could be used to personalize the occupant experience, potentially improving both satisfaction and safety. Recent improvements in 3D camera technology and increased use of cameras in vehicles offer the capability to effectively capture data on vehicle occupant characteristics, including size, shape, posture, and position. In previous work, the body dimensions of standing individuals were reliably estimated by fitting a statistical body shape model (SBSM) to data from a consumer-grade depth camera (Microsoft Kinect). In the current study, the methodology was extended to consider seated vehicle occupants. The SBSM used in this work was developed using laser scan data gathered from 147 children with stature ranging from 100 to 160 cm and BMI from 12 to 27 kg/m2 in various sitting postures. A principal component (PC) analysis was conducted based on these scans along with the manually-measured body landmarks, and 100 PC scores were retained to account for 99% of variance in the body shape and sitting postures. A PC-based fast fitting method was applied to estimate the occupant…
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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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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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Clustering and Scaling of Naturalistic Forward Collision Warning Events Based on Expert Judgments

UMTRI-James Sayer
Ford Motor Co.-Louis Tijerina
Published 2014-04-01 by SAE International in United States
The objectives of this study were a) to determine how expert judges categorized valid Integrated Vehicle-Based Safety Systems (IVBSS) Forward Collision Warning (FCW) events from review of naturalistic driving data; and b) to determine how consistent these categorizations were across the judges working in pairs. FCW event data were gathered from 108 drivers who drove instrumented vehicles for 6 weeks each. The data included video of the driver and road scene ahead, beside, and behind the vehicle; audio of the FCW alert onset; and engineering data such as speed and braking applications. Six automotive safety experts examined 197 ‘valid’ (i.e., conditions met design intent) FCW events and categorized each according to a taxonomy of primary contributing factors. Results indicated that of these valid FCW events, between 55% and 73% could be considered ‘nuisance alerts’ by the driver. These were the FCW alerts presented in benign conditions (e.g., lead-vehicle turning) or as a result of deliberate driver action (aggressive driving). Only 16% of the FCW alerts were attributed to driver distraction and all of these cases…
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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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Characterizing One-day Missions of PHEVs Based on Representative Synthetic Driving Cycles

SAE International Journal of Engines

UMTRI-Zevi Baraket
Univ. of Michigan-Tae-Kyung Lee, Timothy Gordon, Zoran Filipi
  • Journal Article
  • 2011-01-0885
Published 2011-04-12 by SAE International in United States
This paper investigates series plug-in hybrid electric vehicle (PHEV) behavior during one-day with synthesized representative one-day missions. The amounts of electric energy and fuel consumption are predicted to assess the PHEV impact on the grid with respect to the driving distance and different charging scenarios: (1) charging overnight, (2) charging whenever possible. The representative cycles are synthesized using the extracted information from the real-world driving data in Southeast Michigan gathered through the Field Operational Tests (FOT) conducted by the University of Michigan Transportation Research Institute (UMTRI). The real-world driving data include 4,409 trips covering 830 independent days and temporal distributions of departure and arrival times. The sample size is large enough to represent real-world driving. The driving cycle synthesis approach proposed by Lee, and Filipi [2],[3] based on a stochastic process and subsequent validation procedure is used to create real-world driving cycles. To cover the entire range of real-world driving distance, ten synthetic cycles are created ranging from 4.78 miles to 40.71 miles following the real-world driving distance distribution. The PHEV behavior over one-day is…
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