Truck Configurations Research Articles

Highway Infrastructure, Heavy Trucks, and Expert Systems

In an effort to develop tools to help address various aspects of heavy truck size and weight impacts on pavements, bridges, truck safety, and economics, the Roads and Transportation Association of Canada undertakes research to look at the feasibility of applying expert system technology to various aspects of this problem. A prototype expert system capable of assessing the legality of various truck configurations was also developed. The problem definition stage of the work required much greater effort than originally anticipated. Expert systems were found to be applicable in the areas of generating alternative regulations, dealing with operational problems within motor carrier fleets, and in the interpretation of regulations. In other areas, the need for conventional and “hybrid” tools was found. The prototype system addressed the subproblem for which it was conceived, although simplifications were required to achieve this goal within the original budget.

Line haul transport cost and pavement damage characteristics of some Ontario trucks

The factors contributing to the line haul transportation costs of very large trucks operating on the Ontario highway system are calculated from fundamental tractive resistance equations and tractive effort characteristics for two "weigh-out" commodity types and representative haul routes. These calculated costs are compared with some observed costs and earlier analyses to check the validity of the models. The theoretical models are then used to assess the impact on operating costs of a variety of truck parameters which include truck type and tire pressures. The pavement damage created by the different truck types are estimated and the damage costs compared with the savings in line haul transportation costs. It is concluded that the pavement damage impacts of different truck types should be carefully compared with potential line haul transportation cost savings to ensure that allowable truck configurations are economically efficient with respect to both public and private costs. Key words: highway engineering, pavement damage, pavement cost, truck operating cost, vehicle weights.

Effects of environmental variables on truck noise emission and noise propagation to test microphones

If new vehicle noise levels cannot be predicted accurately, manufacturers must overdesign for quietness in order to be sure of meeting noise standards. To determine factors affecting sound levels, nine truck–tractor configurations were tested according to SAE Standard J366b, Exterior Sound Level for Heavy Trucks and Buses during a variety of weather conditions at three, 2‐week intervals over a 6‐month period. Tests made according to the standard produce reasonably repeatable results when a vehicle is tested repeatedly at the same test site (σ≤0.83 dB). There was a statistically significant but weak effect of temperature on the A‐weighted sound level located 15 m from the center line of vehicle travel for three of nine truck test configurations, showing decreasing sound level with increasing temperature. The coefficient of this temperature effect averaged about −0.020 dB per degree Fahrenheit. Sound emission from truck–tractors was affected by temperature for eight of nine truck configurations. Humidity, b...

Spectral Analysis of Freight Car Truck Lateral Response

This paper summarizes methods used to quantify the lateral response of freight car trucks to random track irregularity inputs. Spectral analysis is applied to the results of an extensive series of experiments using a one-fifth scale model of a truck and half carbody, in which all inertial, friction, creep, and stiffness forces are dynamically scaled. The repeatability and confidence limits for estimates of the spectral densities of track inputs and truck response variables are determined. The influence of forward velocity, truck internal friction, and axle load on the dominant truck response modes is presented. Cross spectral methods are used to reference signals to the true track centerline, and to compute lateral response transfer functions and coherence levels. The low levels of coherence between track inputs and freight car truck/carbody response indicate that linear transfer functions do not represent the response adequately, and that measured output spectra are superior to transfer functions for comparison of truck configurations.