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Collisions with young pedestrians often have serious traumatic and financial consequences. Allegations of negligence are frequently made against the drivers of involved vehicles, on the basis that they failed to take evasive action. A key element in determining the time available to the driver to avoid a collision is the speed of the pedestrian. In some instances, the young pedestrian is initially stationary in full view of the driver and then runs into the path of the vehicle. When this occurs, the acceleration of the pedestrian is an important element in determining the available time. This paper reports on accelerations from a standing start and associated walking, jogging and running speeds of pedestrians 5 – 17 years of age. Because children can vary considerably in height and weight for a given age, the effects of height and weight on acceleration and speed are also reported.

A common form of pedestrian accident involves the pedestrian emerging from behind a stopped vehicle, into the path of an oncoming car. A mathematical model (“EMERGE”) has been developed for calculating the time available to the driver to see and avoid the pedestrian. It involves calculating in 2 dimensions the equations of motion of the vehicle and the pedestrian, together with the lines of sight of the driver and the pedestrian around the stopped vehicle. The sensitivity of the model to the different variables is demonstrated. The model allows for deceleration of the car. For any given driver perception-reaction time and car deceleration rate, the model can be used to calculate the maximum speed of the car from which it would have been possible to have avoided the collision by braking to a stop. This can often demonstrate that the driver would only have been able to have avoided the collision if he had driven at an unreasonably low speed.