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This paper provides an overview of the current state of knowledge on medium and heavy truck safety and reviews the results of truck safety research sponsored by the Motor Vehicle Manufacturers Association. A number of issues have been raised about the accident experience of trucks, and the injuries and fatalities sustained by occupants. The diverse viewpoints and perceptions which exist on the reasons for these accidents and what countermeasures should be taken are reviewed. The evolutionary nature of truck accident research is presented, pointing out that sufficient detailed accident and injury data are lacking. Corresponding information on truck configuration, size, weight and exposure data remain inadequate. The role of the vehicle, driver, and highway environment in accident causation must be known and methods to achieve this goal are examined. Despite these limitations, there is progress in understanding the causes of truck accidents.

From various sources of information it is clear that truck noise is a definite public nuisance. Early noise control efforts were very productive in that many heavy duty trucks did not have mufflers, and the addition of this device made clear improvements. Further improvement requires treatment of many sources significant to the overall level. It is felt that today's “tight but attainable” 88 dBA for heavy trucks can reduce to 86 dBA by 1975 and 8k dBA by 1978 with a lot of hard work. There is promise for meaningful noise regulation in the “real world” as indicated by “calibratability” of non-standard sites.

The impact of farm and industrial tractors on the total national emissions picture is difficult to assess because the great diversity of uses for these machines results in a wide variation in duty cycles and degrees of utilization. Also, there is a general lack of detailed information on population and population distribution. This paper compares possible farm tractor duty cycle models and concludes that the widely used 13-mode federal heavy-duty diesel engine emissions test cycle can be used to estimate wheel tractor emissions. Estimates then are given for the amount of pollution released by wheeled farm and industrial tractors in 1972, based on the 13-mode cycle and population estimates derived from U.S. Dept. of Commerce, U.S. Dept. of Agriculture, and Farm and Industrial Equipment Institute data. Calculations show wheeled tractor emissions contribute 3.2% or less of the national total, depending upon the pollutant species.

The Vehicle Maintenance Reporting Standards of the American Trucking Associations can be used by manufacturers to improve heavy-duty vehicles. After verifying the accuracy and significance of the data the manufacturing, engineering, technical service and marketing departments can all use the information to improve vehicles and provide better service to the user.

A method of developing a mathematical model of power-plants to simulate engine-governor, or servo systems on a d-c analog or digital differential analyzer is presented. Based on experimental data, the steady-state output of a powerplant is defined as a function of two variables. The dynamics is defined, and the steady-state performance is corrected for response and inertia effects. The resulting mathematical model is discussed with respect to computer applications, instrumentation, and techniques for compiling empirical data needed. Another application is monitoring performance of farm tractors, industrial equipment, and/or automotive systems under field operating conditions. The mathematical model is simulated by an analogous circuit of components that may be inconspicuously mounted on the powerplant in question.

THE NEW DIESEL ENGINES developed recently by International Harvester are adaptations of existing carbureted truck engines. The manufacturing economies possible by employing existing machine tools were the governing consideration in their design. This paper discusses solutions found to the many problems presented by this approach to engine design: crankshaft, crankcase, connecting rods, pistons, lubricating system, and the like. Extensive interchangeability of parts was a result of the design concept. The engines have been successfully adapted to farm tractors, crawler tractors, stationary motors, and various automotive applications.*