PEDESTRIAN ACCIDENT RECONSTRUCTION

The reconstruction of pedestrain collisions is very dependent on the extent of the evidence gathered at the time of the collision, in particular the point of impact and the subsequent rest position of the pedestrain and the vehicle.

Extensive reseach has been done on estimating impact speed based on the distance that the pedestrain was thrown, on pedestrain walking, jogging and running speeds and on acceleration of a pedestrain from standstill over short distances.

For each case, one of the most important factors is the ammount of time that the pedestrain could be first seen as at risk to being struck by the vehicle. An average reaction time for a driver is 1.5 seconds. This is the time it takes for a driver to see the risk, assess the risk and to apply the brake pedal. In this time the vehicle will continue in its course without any changes to its speed or direction. A vehicle travelling at 50km/h travels a distance of 20.8 metres in 1.5 seconds. There are cases in which the time during which the pedestrain could be seen at risk was less than that of a average driver's reaction time. In these cases there would be no possibility for a driver to avoid the collision and the impact was inevitable.

An animation of a pedestrain collision is represented using the ARAS 360 HD computer program.