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The air movement produced by various types of road vehicles has been experimentally determined in order to evaluate the potential of this air flow to destabilize nearby pedestrians. Six vehicles are used, as small as an automobile and as large as a tractor-trailer combination, driven at speeds ranging from 20 to 50 mph (23 to 80 kph), at distances to sensors of two to six feet (0.6 to 1.8 m), in order to quantify some of the chaotic effects of the air motion generated by these vehicles, and specifically, what destabilizing effect it can have on nearby pedestrians. For each combination of testing variables, the peak air speed, relative temporal gust occurrence, and settling time to ambient conditions were measured. The results are analyzed, and a discussion is provided regarding the relation of factors, such as vehicle speed and the distance to the speed sensor, to the magnitude of the maximum air speed recorded.

In this paper, a two-degree-of-freedom (DOF) dynamic model of an on-highway truck seat is created using the Simulink simulation program from MATLAB. Engineering properties of the seat used in the model are measured in the laboratory, obtained from seat component manufacturers, or estimated using engineering judgment. Modeled parameters include: air spring force, damper force, end-stop force, cushion force, seat belt force, driver mass, and cab vertical oscillations due to road disturbances. The model is developed to facilitate seat design as a means of increasing the comfort level that on-highway truck drivers face while carrying out their everyday tasks. Field testing of the seat is performed in order to validate the model. National Instruments hardware and Labview software are used for the data acquisition.

In this paper, a real-world accident that involved a tractor-semitrailer that lost its brakes on a steep downgrade is analyzed. The crash was caused by brake loss due to massive overheating caused by inoperative brakes, driving too fast for conditions, and driving in an improper gear. The effect on brake temperatures from prior uphill and downhill stretches encountered just before the crash is considered. The crash is analyzed using a Microsoft® Excel spreadsheet-based transient brake model for three sets of published brake temperature modeling methodologies and parameters: The Grade Severity Rating System developed by NHTSA (GSRS), a model developed by the University of Michigan Transportation Research Institute (UMTRI), and a model developed by Rudolf Limpert (Limpert). A fourth and different approach utilized a heavy truck simulation (HVE-SIMON™) with HVE Brake Designer®. The results of this analysis using the four models are compared.

This research compares the responses of a vehicle modeled in the 3D vehicle simulation program SIMON in the HVE simulation operating system against instrumented responses of a 3-axle tractor, 2-axle semi-trailer combination. The instrumented tests were previously described in SAE 2001-01-0139 and SAE 2003-01-1324 as part of a continuous research effort in the area of vehicle dynamics undertaken at the Vehicle Research and Test Center (VRTC). The vehicle inertial and mechanical parameters were measured at the University of Michigan Transportation Research Institute (UMTRI). The tire data was provided by Smithers Scientific Services, Inc. and UMTRI. The series of tests discussed herein compares the modeled and instrumented vehicle responses during quasi-steady state, steady state and transient handling maneuvers, producing lateral accelerations ranging nominally from 0.05 to 0.5 G's.

This paper investigates the coefficients of static and kinetic friction between the hardwood flooring of a used van-type semi-trailer and the bottom surfaces of pallets fabricated from: high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), oak, or hickory. Tests to determine static and kinetic coefficients of friction (COF) were performed with the pallets moving longitudinally or transversely across the cargo trailer floor, and with varying loads. Using a general linear model to analyze the data collected, the best estimates of the COF (static, kinetic) for each pallet were found to be: HDPE (0.31, 0.20), LLDPE (0.29, 0.24), hickory (0.32, 0.21), oak (0.35, 0.25). The analysis also showed that pallet load had a small but statistically significant effect on the friction coefficients.