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This paper describes and compares three methods of estimating the static rollover threshold of passenger cars and light trucks. The Static Stability Factor (SSF), Side Pull Ratio (SPR), and Tilt Table Ratio (TTR) “metrics” are described and methods of measuring each are presented. The comparison of the three metrics is limited to the accuracy, repeatability, and ease of the measurements, and does not attempt to compare their ability to predict real world rollover accident involvement. The results of the comparison have shown that the three metrics are very closely related. Based on this, the rollover accident predictive power of each metric is expected to be similar. However, the ease and accuracy of the TTR measurement make it the most useful of the three. DURING THE 1980's, the use of light trucks and multi-purpose vehicles for basic transportation increased considerably. By 1990, domestic full-size pickup trucks were regularly among the top five passenger vehicles sold.

This paper describes the theory and design of an apparatus, the Suspension Parameter Measurement Device (SPMD), which has been developed to measure the displacements and forces which occur at the road wheels of a vehicle as the body moves, or as lateral and/or longitudinal forces are applied at the tire/road interface. Wheel movements resulting from the bounce, pitch, or roll motions of the vehicle body in the absence of lateral and longitudinal forces at the tire/road interface are the kinematic characteristics of the suspension. Wheel displacements caused by the application of forces in the plane of the road are defined as the compliance characteristics, while those resulting from motions of the steering wheel are the steering characteristics. The purpose of the SPMD is to measure all of these characteristics, thereby providing data for use in the simulation of the performance of cars and light trucks.

This paper summarizes the results of test maneuvers devised to measure on-road, untripped, rollover propensity. Complete findings from this research are contained in [1]. Twelve test vehicles, representing a wide range of vehicle types and classes were used. Three vehicles from each of four categories: passenger cars, light trucks, vans, and sport utility vehicles, were tested. The vehicles were tested with vehicle characterization and untripped rollover propensity maneuvers. The vehicle characterization maneuvers were designed to determine fundamental vehicle handling properties while the untripped rollover propensity maneuvers were designed to produce two-wheel lift for vehicles with relatively higher rollover propensity potential. The vehicle characterization maneuvers were Pulse Steer, Sinusoidal Sweep, Slowly Increasing Steer, and Slowly Increasing Speed. The rollover propensity maneuvers were J-Turn, J-Turn with Pulse Braking, Fishhook #1 and #2, and Resonant Steer.

According to NHTSA's 2011 Traffic Safety Facts [1], passenger vehicle occupant fatalities continued the strong decline that has been occurring recently. In 2011, there were 21,253 passenger vehicles fatalities compared to 22,273 in 2010, and that was a 4.6% decrease. However; large-truck occupant fatalities increased from 530 in 2010 to 635 in 2011, which is a 20% increase. This was a second consecutive year in which large truck fatalities have increased (9% increase from 2009 to 2010). There was also a 15% increase in large truck occupant injuries from 2010. Moreover, the fatal crashes involving large trucks increased by 1.9%, in contrast to other-vehicle-occupant fatalities that declined by 3.6% from 2010. The 2010 accident statistics NHTSA's report reveals that large trucks have a fatal accident involvement rate of 1.22 vehicles per 100 million vehicle miles traveled compared to 1.53 for light trucks and 1.18 for passenger cars.

This paper presents an overview of currently ongoing research by the National Highway Traffic Safety Administration (NHTSA) in the area of light vehicle (passenger cars and light trucks) Antilock Brake Systems (ABS). This paper serves as a lead-in to other papers that will be presented during this session. Several statistical crash data studies have found there to be little or no net safety benefit from the implementation of four-wheel ABS on passenger automobiles. Typically, these studies have found ABS to be associated with: 1. A statistically significant decrease in multi-vehicle crashes. 2. A statistically significant decrease in fatal pedestrian strikes. 3. A statistically significant increase in single-vehicle road departure crashes. The safety disbenefit due to the third finding approximately cancels the safety benefits from the first two findings.