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Electrochromic rearview mirrors can provide continuous levels of reflectivity and unobtrusive, automatic control. The availability of this technology has increased the importance of understanding how to select the best level of reflectivity for a given set of lighting conditions. For night driving with glare from following headlights, the best reflectivity level will always depend on a tradeoff among several variables. This study was designed to help clarify what variables are important and how they should be quantified. Twenty subjects, 10 younger and 10 older, performed a number of visual tasks while viewing stimuli through an electrochromic rearview mirror. Subjects were seated in an automobile mockup in a laboratory, and the reflectivity level of the mirror was changed before each of a series of discrete trials. On each trial, subjects saw reflected in the mirror a visual-acuity stimulus and a glare source of varying intensity.

Directional performance characteristics of heavy truck combinations are reviewed with respect to the influences of multiple axles and articulation points. The performance characteristics considered include steady turning, directional stability, and forced responses in obstacle avoidance maneuvers. The review provides useful insights to engineers interested in the handling and safety qualities of these types of vehicles.

The implications of restricting axle loads to preserve pavements while at the same time allowing gross combination weights over 80,000 pounds are examined with respect to the design qualities of the types of heavy trucks that might be developed. The proposed vehicles would have more axles than current designs thereby achieving higher gross combination weights with smaller axle loads. Design factors influencing mobility, productivity, preservation of the highway infrastructure, and performance in safety-related maneuvers are discussed.

A method is presented for checking vehicle designs to see if they will meet size and weight rules that may be applicable to vehicles weighing more than 80,000 lb. Then, examples of heavy trucks that have been designed to be productive are used in illustrating analytical evaluations of measures of performance in safety-related maneuvering situations. The paper concludes with the point of view that trucks over 80,000 lb could have design attributes that would allow these heavier vehicles to have levels of intrinsic safety exceeding or comparable to those of current trucks.

The side impact, recently and currently the subject to of much debate, controversy and proposed NHTSA rule making, is a difficult type of crash to significantly reduce serious injuries and fatalites. Results from real-world crash investigations presents a confusing picture for the near-side passenger compartment crash. A direct relationship between the amount of crush and injury severity levels (MAIS) is not apparent. Exemplar cases of tow-a-way/injury crashes are presented at all AIS injury level of drivers in crashes with direct driver door crush damage.

This paper discusses techniques developed and used by the Biosciences Group at the University of Michigan Transportation Research Institute (UMTRI) for measuring three-dimensional head motion, skull bone strain, epidural pressure, and internal brain motion of repressurized cadavers and Rhesus monkeys during head impact. In the experimental design, a stationary test subject is struck by a guided moving impactor of 10 kg (monkeys) and 25 or 65 kg (cadavers). The impactor striking surface is fitted with padding to vary the contact force-time characteristics. The experimental technique uses a nine-accelerometer system rigidly affixed to the skull to measure head motion, transducers placed at specific points below the skull to record epidural pressure, repressurization of both the vascular and cerebrospinal systems, and high-speed cineradiography (at 1000 frames per second) of radiopaque targets.

As a result of improved educational opportunities, handicapped children have increased exposure to transportation related risks. Many of these children require specialized orthopedic seating and posture control devices and must remain in them while riding in a vehicle. The lack of impact protection features in these seating devices introduces an unnecessary level of risk. The emphasis of this program was to demonstrate that proven restraint principles could be applied to handicapped seating without compromising the medical requirements of these units. Efforts were concentrated on two such systems: a molded-shell orthotic seat and a stroller-type Travel Chair. Sled impact tests at 30 mph and 20 g's were used to assist in the evaluation of the upgraded restraints. The results have been encouraging and have shown that handicapped seating can supply the same level of crash protection provided by conventional child restraint systems.

A test series using unembalmed cadavers was conducted to investigate thoracic response differences in lateral impacts between high energy (rib fractures produced) and low energy (no rib fractures produced) testing and also the response to low energy impacts for different impact directions (frontal, 45°, and lateral). Five of the test subjects were instrumented with a nine-accelerometer package and an eighteen-accelerometer array to measure thoracic response. Seven of the test subjects were instrumented with a triaxial accelerometer on the head and a six-accelerometer array to measure thoracic response. Impact events were performed with either the UMTRI pendulum impact device or the UMTRI pneumatic impact device. The subject was struck with a free-traveling mass (25 or 56 kg) which was fitted with either a 15 cm round or 20 cm square rigid metal surface.

This paper describes the methodology and results from a project involving development of anthropometrically based design specifications for a family of advanced adult anthropomorphic dummies. Selection of family members and anthropometric criteria for subject sample selection were based on expected applications of the devices and on an analysis of U.S. population survey data. This resulted in collection of data for dummy sizes including a small female, a mid-sized male, and a large male. The three phases of data collection included: 1. in-vehicle measurements to determine seat track position and seating posture preferred by the subjects for use in development of laboratory seat bucks; 2. measurement of subject/seat interface contours for fabrication of an average hard seat surface for use in the buck; and 3. measurement of standard anthropometry, seated anthropometry (in the buck), and three-dimensional surface landmark coordinates using standard and photogrammetric techniques.

A test series using eight unembalmed cadavers was conducted to investigate factors affecting the creation of cervical spine damage from impact to the crown of the head. The crown impact was accomplished by a free-fall drop of the test subject onto a load plate. The load plate striking surface was covered with padding to vary the contact force time characteristics. The orientations of the head, cervical spine, and torso were adjusted relative to a laboratory coordinate system to investigate the effects of head and spinal configuration on the damage patterns. Load and acceleration data are presented as a function of time and as a function of frequency in the form of mechanical impedance.

The purpose of this paper is to describe a combination of state-of-the-art detailed accident investigation procedures, computerized vehicle crash and occupant modeling, and biomechanical analysis of human injury causation into a method for obtaining enhanced biomechanical data from car crashes. Four accident cases, out of eighteen investigated, were selected for detailed reconstruction. Three were frontal impacts while the fourth was lateral. The CRASH II and MVMA 2-D analytical models were used in the reconstruction process. Occupant motions, force interactions with vehicle components, accelerations on the various body segments, and much other information was produced in the simulation process and is reported in this paper along with scene and injury data from the accidents.