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This study was performed in order to evaluate the accuracy with which pedestrians estimate the speed of nearby automobiles. A total of 87 subjects were involved in this experiment, with 487 useful speed estimates being obtained from them. The vehicle speeds were measured using radar guns, and the moving cars were located upstream, downstream, and adjacent to the subjects. A survey form was used to obtain attributes about each subject. A multivariate regression was used to allocate portions of the variation in the percent error among the various factors that describe the subject and the moving vehicle. Statistical significance was discovered for the main effects and some interactions among: gender, driving experience, a self-assessment of ability to estimate such speeds, the use of the posted speed limit, the speed of the target vehicle, and the location of the vehicle on the roadway.

In order to evaluate the variation in distance estimation accuracy, a survey was conducted during which 123 subjects estimated distances to static objects in a roadway setting. The subjects (which included many police officers) tended to underestimate distances to objects that were from 21 to 383 feet away; the average estimation error was −8.6% while the median error was − 22%. The variation in performance among individuals was extremely large, with extreme errors ranging from − 96% to + 811%. The distribution of error did not conform to a Gaussian (normal) distribution because of the skew of the observed error distribution towards large positive errors. Box plots were used to identify nine “outlier” respondents who produced a total of 15 error estimates which were extraordinary in their difference from the rest of the data.

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.

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.

This paper investigates the coefficients of static and kinetic friction between the hardwood flooring of a used semi-trailer and the bottom surfaces of both an old and a new hardwood pallet, with varying cargo weights, at varying locations in the trailer. A total of 22 tests were performed with the pallets moving parallel to the longitudinal axis of the trailer and perpendicular to this axis. The results show that the variations in load did not statistically affect the friction coefficients. The older pallet had statistically smaller static and kinetic friction coefficients (s=0.32, k=0.26) than that of the newer pallet (s=0.35, k=0.29). The static friction coefficients were statistically dependent upon whether the test took place at the front (0.36), middle (0.34) or rear (0.32) of the semi-trailer. Kinetic coefficients behaved similarly: front (0.29), middle (0.27) or rear (0.26).

The transporting of live cattle involves the use of Class 8 tractors and livestock semi-trailers for transportation from farms and feedlots to processing plants. This travel may include unimproved roads, local streets, two lane highways, as well as interstate highways. Typically, cattle are compartmentalized in a “double deck” fashion as it provides utility and comports with size and weight limits for commercial Class 8 vehicles. Concern has been expressed for the effect of cattle movement upon the dynamic performance of the loaded Class 8 tractor-livestock trailer assembly. Loading guidelines exist for cattle that attempt to prevent injury or debilitation during transit, and literature exists on the orientation and some kinematics of loaded cattle. Considerable literature exists on the effect of liquid slosh in tankers and swinging beef carcasses suspended from hooks in refrigerated van trailers on the dynamic response and roll stability of those vehicles.