Showing papers by "Kenneth L. Campbell published in 1991"

Center of gravity height: a round-robin measurement program

Abstract: A round-robin center of gravity height measurement study was conducted to assess current practice in the measurement of the vertical position of the center of gravity (c.g.) of light truck-type vehicles. The study was performed by UMTRI for the Mototr Vehicle Manufacturers' Association. Chrysler, Ford, General Motors and the National Highway Traffic Safety Administration perticipated. The primary objectives were (i) to determine to what extent the differing experimental procedures currently used by the participating laboratories result in significant differences in the measured vertical position of the center of mass of light truck-type vehicles, and (ii) to gain insight into the physical causes of such differences. The results of the program shoved (i) that there were significant differences between the c.g. height measurement results obtained by different laboratories, (ii) repeatability of results within the individual laboratories was generally good, and (iii) close examination of the individual procedures tended to explain the differences in results between laboratories, this providing the expecctation that variability in this regard could be significantly reduced.

Differential truck accident rates for michigan

Abstract: Major changes in the trucking industry have resulted from federal legislation that relaxed the regulation of trucks in interstate commerce, allowed the use of double-trailer combinations nationwide on Interstate highways, and required states to regulate trailer length instead of overall length. Because Michigan has long had extremely liberal truck size and weight regulations, its experience with truck safety is of significant interest. A project by the University of Michigan and Michigan State University was undertaken to develop statistical information on accidents, travel, and the risk of accident involvement for Michigan-registered trucks in Michigan. The study objective was to calculate disaggregate truck accident rates by road class, day or night, and urban or rural operating conditions for tractors without trailers (bobtails) and in single- and double-trailer configurations. Major findings included the following: bobtails consistently have the highest accident rates; all-accident and casualty rates for single and double configurations are similar to one another; the most significant and consistent factor associated with truck accident rates was the roadway class (highest rates on the "local" road system, lowest on limited-access highways); urban accident rates were lower than rural rates; night rates were higher than day rates for casualty accidents but lower for all accidents; and tractor drivers aged 19-20 have an accident rate five times the average. The findings indicate that differences in truck safety by roadway class are more important than those between singles and doubles. Discussion and recommendations concerning improvements in truck accident and exposure data as well as further work on the relationship between truck accidents and geometry are included.

Development of a collision typology for evaluation of collision avoidance strategies

Abstract: This paper summarizes the results of an effort to identify and rank vehicle collision scenarios in order to create a "collision typology" that could aid in the assessment of the potential benefit of accident avoidance technologies Data from four computerized accident files were used to construct an I8-level collision configura- tion variable This variable includes the number of vehicles involved, their relative orientation, intent to turn, relation to intersection, and traffic control at the intersection Distributions of the collision configuration variable were generated for several factors of interest using 1989 ~ichi~n data Five of the most prevalent collision types were selected for more detailed review based on the original police accident reports The case studies lent addi- tional insight into the circumstances of different accident types Among other findings, the review suggested that in collisions at nonsignaliied intersections, older drivers often stopped and then pulled out into oncoming traffic,

Large-truck travel estimates from the national truck trip information survey

Abstract: The methodology of the National Truck Trip Information Survey conducted by the Center for National Truck Statistics of the University of Michigan Transportation Research Institute is described in this paper. The survey was conducted to achieve the two main goals of estimating the registered large truck population of the continental United States and providing detailed data on its annual mileage. Travel in the file can be cross-classified by road type, area type, and time of day, and broken down according to truck configuration, cargo body style, cargo type and weight, gross weight, number of axles, and driver characteristics. This type of detail is useful in risk assessment, because the risk of accident involvement depends on the operating environment as well as the physical characteristics of the truck.

Methodology for the development of collision avoidance strategies based on accident data

Abstract: This paper presents a proposed approach to the analysis of accident data in support of the development of collision avoidance technology. The preliminary results of an effort to identify and rank collision situations on the basis of a "collision typology" are summarized for four databases. An 18-level collision configuration variable was constructed which included the number of vehicles involved, their relative orientation, intent to turn, relation to intersection, and traffic control at the intersection. "Contributing factors" are defined and identified on the basis of statistical associations between the levels of the factors and the categories of the collision typology. Five of the most prevalent collision types were selected for more detailed review based on a probability-based sample of the original police accident reports.

Heavy truck safety in michigan

Abstract: This article discusses problems related to truck safety including truck exposure data and truck crash data, and summarizes findings of recent research in Michigan. It also suggests directions for future work. It is noted that the differences in safety (as measured by involvement in traffic crashes) between singles and doubles are fairly small and, when only multivehicle crashes are considered, doubles are probably safer. The Michigan study found that, in general, doubles in Michigan are probably safer overall. The study has also shown that truck safety decreases as one moves down the hierarchy of the highway system - the more restrictive geometry of nonlimited-access highways and local roads leads to higher crash rates.