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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.

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 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.