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This paper examines truck driver injury and loss of life in truck crashes related to cab crashworthiness. The paper provides analysis of truck driver fatality and injury in crashes to provide a better understanding of how injury occurs and industry initiatives focused on reducing the number of truck occupant fatalities and the severity of injuries. The commercial vehicle focus is on truck-tractors and single unit trucks in the Class 7 and 8 weight range. The analysis used UMTRI's Trucks Involved in Fatal Accidents (TIFA) survey file and NHTSA's General Estimates System (GES) file for categorical analysis and the Large Truck Crash Causation Study (LTCCS) for a supplemental clinical review of cab performance in frontal and rollover crash types. The paper includes analysis of crashes producing truck driver fatalities or injuries, a review of regulatory development and industry safety initiatives including barriers to implementation.

Heavy truck rollover remains a primary factor in truck driver fatalities and injury. Roll stability control (RSC) and electronic stability control (ESC) are technologies that have been introduced to reduce the incidence of rollover in heavy truck crashes. This report provides an analysis of the real-world experience of a large for-hire company that introduced RSC into its fleet starting in 2004. The carrier provided a well-documented set of data on the operations of its truck-tractors, including both those equipped with RSC and those that did not have RSC installed. The purpose of the analysis is to determine the effect of RSC on the probability of rollover, as well as to identify other factors that either contribute to rollover or help reduce its incidence. This study presents results on the incidence of rollover both in terms of rollovers per 100 million miles traveled and the percentage of crashes that resulted in rollover.

This paper examines how commercial vehicle aerodynamic improvements can be influenced by regulation particularly with respect to size and weight policy. It discusses the potential use of performance based standards (PBS) first introduced to optimize vehicle configurations in terms of vehicle stability and control and compatibility with highway geometry. There are several vehicle treatments that can be used to reduce aerodynamic drag, some of which lengthen or widen the vehicle without increasing cargo capacity. One such solution is referred to as ‘boat tails” consisting of a light weight external extension of the trailer allowing the air flow to remain attached as the vehicle cross section diminishes resulting in a reduction in the area of negative pressure at the end of the vehicle which reduces drag force.

This paper contains an analysis of the potential safety benefits of electronic stability control (ESC) for single unit trucks and tractor semitrailers within the U.S. operating environment. It is based on research projects [1,2] which combined hardware-in-the-loop simulation and vehicle testing with the analysis of independent crash datasets using engineering and statistical techniques to estimate the probable safety benefits of stability control technologies for 5-axle tractor-semitrailer vehicles and single unit trucks. The characteristics of ESC-relevant crashes involving these two vehicle classes were found to be very different as were the control strategies needed for crash avoidance. Rollover was the dominant ESC relevant crash type for tractor semitrailers while loss of control was the dominant ESC relevant crash for straight trucks.

The use of dampers (shock absorbers) in heavy truck suspensions is central to reducing dynamic wheel loads. Dynamic wheel loads are responsible for a significant component of vehicle related road damage. Improving the viscous damping characteristics of suspensions will substantially reduce dynamic wheel loads thereby enhancing suspension “road-friendliness”. Because dampers deteriorate over time, a new test is required to determine the in-service condition of dampers. There is a need to develop improved dampers that are optimized to reduce dynamic wheel loads while providing good ride quality. They must be sufficiently robust to dissipate the required energy from various magnitudes of road unevenness over extended life cycles.