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Pedestrian collisions are primarily a disease of urban streets and intersections, where both pedestrian and automobile traffic are in high volume. City engineers and planners are plagued with the problem of mitigating the number of pedestrian/vehicle collisions while maintaining traffic flow. In an attempt to study the problem in depth, city engineers in Helsinki, Finland placed a camera in a bus station clock tower overlooking a busy downtown intersection in February of 1991. The camera was placed at the intersection to study pedestrian and vehicle behavior at the intersection and to quantify the speeds of the respective parties. Since its installation, the camera has witnessed fifteen pedestrian/vehicle accidents. Detailed measurements of the intersection were taken for analysis of the accidents. The intersection was also calibrated with the camera in place for use of the digitizing system.

Determination of vehicle speed at the time of impact is frequently an important factor in accident reconstruction. In many cases some evidence may indicate that the brake pedal of a striking vehicle was disengaged, and the vehicle was permitted to idle forward prior to impacting the target vehicle. This study was undertaken to analyze the kinematic response of various vehicles equipped with automatic transmissions while idling, with the transmissions in drive and the brake pedals disengaged. An array of sedans, SUV's and pickup trucks were tested under 3 roadway conditions (flat, medium slope and high slope). The vehicle responses are reported and mathematical relationships were developed to model the idle velocity profiles for flat and sloped roadway surfaces.