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A comprehensive analysis method for assessing the vehicle impact speed in a vehicle/pedestrian collision was presented in an earlier publication (SAE #2000-01-0846) by the above authors [1]. This presented method provides a practical analytical approach for evaluating vehicle impact speed from the post-impact vehicle damage, pedestrian injuries and pedestrian throw distance. The applicability of this method to reconstructing real world vehicle/pedestrian collisions is examined. The results of this study indicate that the previously presented model can be used to assess a reasonable range for the vehicle impact speed in a vehicle/pedestrian collision. The regression model equations were revised to include the new data.

Lane change maneuvers are often implemented in typical driving applications and more severe swerving maneuvers are occasionally performed in order to avoid motor vehicle collisions. For accident reconstruction purposes, it is necessary to accurately model the vehicle motion and driver response during a lane change maneuver. A theoretical lane change model was developed in order to determine the expected vehicle dynamics including lateral, longitudinal and angular vehicle displacements during the lane change maneuver. This model is based on the vehicle speed, peak and average accelerations, and driver steering input. The theoretical model was then compared to a limited number of real world staged lane change maneuvers conducted with instrumented vehicles over a small range of speeds, accelerations and displacements. The lane change model was found to closely simulate the vehicle motion as recorded during the staged tests.

This paper provides a reference for “real world” walking speeds of young pedestrians. The subjects of the study were unaware elementary school children crossing at marked crosswalks adjacent to elementary schools. The unaware pedestrians were videotaped at 30 frames/second with a camera hidden in a parked vehicle that was not visible from the crosswalks. The pedestrians' constant walking speeds were ascertained from analysis of the video recording. The walking speed data was categorized according to gender, estimated age, number of pedestrians in a group and time of day. The observed trends were compared to data from existing studies.

This paper investigates the accuracy of vehicle pre-braking speed estimates based upon tire/roadway coefficient of friction (drag factor) measurements and skid mark measurements. Data was collected to determine if there were any correlations between pre-braking speeds and pre-skidding speeds. Braking tests were performed on three vehicles using various measurement devices including an accelerometer, a fifth wheel, a radar gun, and a shot marker (bumper gun) system. The vehicle speeds, braking distances, skid mark distances, and deceleration histories were recorded. From this data, coefficients of friction for the tested road surface were evaluated. The coefficients of friction were then used in combination with the measured skid mark distances to calculate the vehicle pre-skidding speeds. The calculated pre-skidding speeds were then compared to the actual pre-braking speeds of the vehicles in order to establish the accuracy of the calculation methodology.

This paper presents a comprehensive method for assessing the vehicle impact speed in a vehicle/pedestrian collision. Mathematical models, real world collision data and staged impact test data were referenced from several studies pertaining to pedestrian collisions. Applicable relationships comparing vehicle impact speed to pedestrian throw distance were developed from regression analyses. In addition, post-impact vehicle damage and pedestrian injuries were subjectively analyzed to assess trends in vehicle impact speed. These methods provide a practical analytical approach for evaluating vehicle impact speed from the post-impact vehicle damage, pedestrian injuries and pedestrian throw distance.

This paper quantifies the deceleration of motor vehicles as they were routinely stopped for an expected hazard in a real world environment. It was observed that the deceleration rate varied non-linearly, with a peak value of about 0.25g as the vehicle decelerated through the speed range of 20 to 30 km/h. This deceleration pattern was common to all evaluated categories of passenger vehicles. A mathematical model was developed to define the deceleration profile; enhancement of this model yielded predictive relations for the velocity, position and remaining braking time of decelerating passenger vehicles.

This paper presents a practical analytical approach for evaluating sideswipe collision severity from residual vehicular deformation. A simplified mathematical procedure was developed to evaluate vehicular speed changes, effective average vehicular acceleration rates and the collision duration from measurements of vehicular damage. Several series of sideswipe collisions were staged to acquire empirical sliding contact data. The results of this testing were employed to provide a preliminary validation of the proposed analysis model. The limited validation supported the use of the proposed analysis technique to assess a vehicle's speed change resulting from a sideswipe collision.