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A new method is presented for physically measuring drivers' field of view in rearview mirrors. A portable coordinate measurement apparatus (FARO Arm) is used to measure the mirror locations, contours, and curvature. Measurements of the driver's head and eye locations while looking into each mirror are also made. Raytracing is used to map the two- or three-dimensional field of view in each mirror. The method differentiates between monocular, binocular, and ambinocular fields of view, and can account for head movements. This method has been applied to passenger cars, light trucks, and heavy trucks to document how drivers aim their mirrors during normal use.

The reach capability of drivers is currently represented in vehicle design practice in two ways. The SAE Recommended Practice J287 presents maximum reach capability surfaces for selected percentiles of a generic driving population. Driver reach is also simulated using digital human figure models. In typical applications, a family of figure models that span a large range of the target driver population with respect to body dimensions is positioned within a digital mockup of the driver's workstation. The articulated segments of the figure model are exercised to simulate reaching motions and driver capabilities are calculated from the constraints of the kinematic model. Both of these current methods for representing driver reach are substantially limited. The J287 surfaces are not configurable for population characteristics, do not provide the user with the ability to adjust accommodation percentiles, and do not provide any guidance on the difficulty of reaches that are attainable.

This paper presents a laboratory study of body dimensions, seated posture, and seatbelt fit for children weighing from 40 to 100 lb (18 to 45 kg). Sixty-two boys and girls were measured in three vehicle seats with and without each of three belt-positioning boosters. In addition to standard anthropometric measurements, three-dimensional body landmark locations were recorded with a coordinate digitizer in sitter-selected and standardized postures. This new database quantifies the vehicle-seated postures of children and provides quantitative evidence of the effects of belt-positioning boosters on belt fit. The data will provide guidance for child restraint design, crash dummy development, and crash dummy positioning procedures.

Vehicle motions can adversely affect the ability of a driver or occupant to quickly and accurately push control buttons located in many advanced vehicle control, navigation and communications systems. A pilot study was conducted using the U.S. Army Tank Automotive and Armaments Command (TACOM) Ride Motion Simulator (RMS) to assess the effects of vertical ride motion on the kinematics of reaching. The RMS was programmed to produce 0.5 g and 0.8 g peak-to-peak sinusoidal inputs at the seat-sitter interface over a range of frequencies. Two participants performed seated reaching tasks to locations typical of in-vehicle controls under static conditions and with single-frequency inputs between 0 and 10 Hz. The participants also held terminal reach postures during 0.5 to 32 Hz sine sweeps. Reach kinematics were recorded using a 10-camera VICON motion capture system. The effects of vertical ride motion on movement time, accuracy, and subjective responses were assessed.

The ASPECT (Automotive Seat and Package Evaluation and Comparison Tools) manikin provides new capabilities for vehicle and seat measurement while maintaining continuity with previous practices. This paper describes how the manikin is used in the development of new designs, the audit verification of build, and in benchmarking competitive vehicles and seats. The measurement procedures are discussed in detail, along with the seat and package dimensions that are associated with the new tool.

The ASPECT program was conducted to develop new Automotive Seat and Package Evaluation and Comparison Tools. This paper presents a summary of the objectives, methods, and results of the program. The primary goal of ASPECT was to create a new generation of the SAE J826 H-point machine. The new ASPECT manikin has an articulated torso linkage, revised seat contact contours, a new weighting scheme, and a simpler, more user-friendly installation procedure. The ASPECT manikin simultaneously measures the H-point location, seat cushion angle, seatback angle, and lumbar support prominence of a seat, and can be used to make measures of seat stiffness. In addition to the physical manikin, the ASPECT program developed new tools for computer-aided design (CAD) of vehicle interiors. The postures and positions of hundreds of vehicle occupants with a wide range of body size were measured in many different vehicle conditions.

Current ATD positioning practices depend on seat track position, seat track travel range, and design seatback angle to determine appropriate occupant position and orientation for impact testing. In a series of studies conducted at the University of Michigan Transportation Research Institute, driver posture and position data were collected in forty-four vehicles. The seat track reference points currently used to position ATDs (front, center, and rear of the track) were found to be poor predictors of the average seat positions selected by small female, midsize male, and large male drivers. Driver-selected seatback angle was not closely related to design seatback angle, the measure currently used to orient the ATD torso. A new ATD Positioning Model was developed that more accurately represents the seated posture and position of drivers who match the ATD statures.

This paper describes the development of the fixed seat eyellipse in the October 2008 revision of SAE Recommended Practice J941. The eye locations of 23 men and women with a wide range of stature were recorded as they sat in each of three second-row bench seats in a laboratory mockup. Testing was conducted at 19-, 23-, and 27-degree seat back angles. Regression analysis demonstrated that passenger eye location was significantly affected by stature and by seat back angle. The regression results were used to develop an elliptical approximation of the distribution of adult passenger eye locations, applying a methodology previously used to develop the driver eyellipse in SAE J941-2002.

A new approach to driver seat-position modeling is presented. The equations of the Seating Accommodation Model (SAM) separately predict parameters of the distributions of male and female fore/aft seat position in a given vehicle. These distributions are used together to predict specific percentiles of the combined male-and-female seat-position distribution. The effects of vehicle parameters-seat height, steering-wheel-to-accelerator pedal distance, seat-cushion angle, and transmission type-are reflected in the prediction of mean seat position. The mean and standard deviation of driver population stature are included in the prediction for the mean and standard deviation of the seat-position distribution, respectively. SAM represents a new, more flexible approach to predicting fore/aft seat-position distributions for any driver population in passenger vehicles. Model performance is good, even at percentiles in the tails of the distribution.

A study of automotive seating comfort and related design factors was conducted, utilizing subjective techniques of seat comfort assessment and objective measures of the seat/subject interaction. Eight male subjects evaluated four different test seats during a short-term seating session and throughout a three-hour driving simulation. For the latter, subjects operated a static laboratory driving simulator, performing body-area discomfort evaluations at thirty-minute intervals. Cross-modality matching (CMM), a subjective assessment technique in which a stimulus is rated by matching to the level of another stimulus, was used during the long-term driving simulation to evaluate discomfort. Subject posture, muscle activity in the lower back and abdomen, and pressure levels at key support locations on the seat were monitored. In addition, a sonic digitizing system was used to record seat indentation contours and to characterize the subjects' spinal contours.

Human figure models are commonly used to facilitate ergonomic assessments of vehicle driver stations and other workplaces. One routine method of workstation assessment is to conduct a suite of ergonomic analyses using a family of boundary manikins, chosen to represent a range of anthropometric extremes on several dimensions. The suitability of the resulting analysis depends both on the methods by which the boundary manikins are selected and on the methods used to posture the manikins. The automobile driver station design problem is used to examine the relative importance of anthropometric and postural variability in ergonomic assessments. Postural variability is demonstrated to be nearly as important as anthropometric variability when the operator is allowed a substantial range of component adjustment. The consequences for boundary manikin procedures are discussed, as well as methods for conducting accurate and complete assessments using the available tools.

The WorldSID project is a global effort to design a new generation side impact crash test dummy under the direction of the International Organization for Standardization (ISO). The first WorldSID crash dummy will represent a world-harmonized mid-size adult male. This paper discusses the research and rationale undertaken to define the anthropometry of a world standard midsize male in the typical automotive seated posture. Various anthropometry databases are compared region by region and in terms of the key dimensions needed for crash dummy design. The Anthropometry for Motor Vehicle Occupants (AMVO) dataset, as established by the University of Michigan Transportation Research Institute (UMTRI), is selected as the basis for the WorldSID mid-size male, updated to include revisions to the pelvis bone location. The proposed mass of the dummy is 77.3kg with full arms. The rationale for the selected mass is discussed. The joint location and surface landmark database is appended to this paper.

Assessments of reach capability using human figure models are commonly performed by exercising each joint of a kinematic chain, terminating in the hand, through the associated ranges of motion. The result is a reach envelope determined entirely by the segment lengths, joint degrees of freedom, and joint ranges of motion. In this paper, the validity of this approach is assessed by comparing the reach envelopes obtained by this method to those obtained in a laboratory study of men and women. Figures were created in the Jack human modeling software to represent the kinematic linkages of participants in the laboratory study. Maximum reach was predicted using the software's kinematic reach-envelope generation methods and by interactive manipulation. Predictions were compared to maximum reach envelopes obtained experimentally. The findings indicate that several changes to the normal procedures for obtaining maximum reach envelopes for seated tasks are needed.

A new method of predicting automobile occupant posture is presented. The Cascade Prediction Model approach combines multiple independent predictions of key postural degrees of freedom with inverse kinematics guided by data-based heuristics. The new model, based on posture data collected in laboratory mockups and validated using data from actual vehicles, produces accurate posture predictions for a wide range of passenger car interior geometries. Inputs to the model include vehicle package dimensions, seat characteristics, and occupant anthropometry. The Cascade Prediction Model was developed to provide accurate posture prediction for use with any human CAD model, and is applicable to many vehicle design and safety assessment applications.

The factors that influence airbag-induced upper-extremity injuries sustained by drivers were investigated in this study. Seven unembalmed human cadavers were used in nineteen direct-forearm-interaction static deployments. A single horizontal-tear-seam airbag module and two different inflators were used. Spacing between the instrumented forearm and the airbag module was varied from 10 cm to direct contact in some tests. Forearm-bone instrumentation included triaxial accelerometry, crack detection gages, and film targets. Internal airbag pressure was also measured. The observed injuries were largely transverse, oblique, and wedge fractures of the ulna or radius, or both, similar to those reported in field investigations. Tears of the elbow joint capsule were also found, both with and without fracture of the forearm.

In the mid 1970s, UMTRI investigated the biomechanical properties of the head and neck using 180 “normal” adult subjects selected to fill eighteen subject groups based on age (young, mid-aged, older), gender, and stature (short, medium, and tall by gender). Lateral-view radiographs of the subjects’ cervical spines and heads were taken with the subjects seated in a simulated automotive neutral posture, as well as with their necks in full-voluntary flexion and full-voluntary extension. Although the cervical spine and lower head geometry were previously measured manually and documented, new technologies have enabled computer digitization of the scanned x-ray images and a more comprehensive and detailed analysis of the variation in cervical spine and lower head geometry with subject age, stature, and gender. After scanning the radiographic images, 108 skeletal landmarks on the cervical vertebrae and 10 head landmarks were digitized.

Improvements in the accessibility and ease of use of seatbelts require an understanding of driver belt donning behavior. Participants in a study of driving posture were videotaped as they put on their belts in their own vehicles, either an SUV or a midsize sedan. The participants were unaware that the purpose of the videotaping was related to the seatbelt. Videos from 95 men and women were analyzed to identify several categories of belt-donning behavior and to analyze the influence of body dimensions. The results have applicability to seatbelt system design, including the use of human figure models to assess seatbelt accessibility.

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.

Contact between the knees and knee bolster commonly occurs in frontal collisions. The contact region on the bolster and the knee anatomy involved are related to the pre-crash positioning of the knees. The location of the distal (or infra-) patella was recorded on volunteers of widely varying stature after they had selected a comfortable driving position in mockups of three vehicles representing a large variation in size and shape: sedan, crossover SUV, and full-size pickup. On average, the right knees were grouped more tightly and were located more forward and lower than the left knees. On average, the knees were positioned 200 mm from the knee bolster for all subjects. The range of distance separating the distal patellae (within subject knee-to-knee distance) varied from 184–559 mm for all subjects for the three vehicles.

Children who are too large for harness restraints but too small to obtain good restraint from a vehicle seatbelt alone should be seated in a belt-positioning booster. Boosters have been shown to significantly reduce abdominal injuries caused by seatbelts. This effectiveness may be due in part to the fact that boosters reduce the effective seat cushion length, allowing children to sit more comfortably without slouching. NHTSA recommends that children who do not use harness restraints use boosters until they are at least 145 cm tall. In this paper, data from several sources were combined to assess how well children fit on rear seat cushions. Data from NASS-GES were analyzed to determine the age distribution of rear-seat occupants. Anthropometric data from several sources were analyzed to determine the distribution of buttock-popliteal length, a measure of thigh length that is a key determinant of seat fit, as a function of age and gender.