Via free -software we analyzed a movie (broadcast on internet) tha t shows a vehicle crashing rolling pedestrians over the westminster bridge in london. Conditioning the perspective and contrast of the frames, we used part of the bridge'S architectural structure to define a metric scale. The program allowed to monitor the vehicle to mark its spatial coordinates as a function of time; By means of a linear regression, we measured the speed during the impacts: 50.08 km/h, with a relative error of 19.2%. In the same film an object in free fall was observed, from the bridge to the river thames, it is inferred that it is a person previously impacted. The analysis obtained shows that the body'S center of mass reached up to 5 m in height and at the time of the collision, at least, it acquired a speed of 32 km/h, with a relative err or of 7.3%. The information is consistent with the specialized literature, but disagrees with the journalistic data. As far as we know, this is the first report that uses both a means and tools available to the public to put into detail the quantitative scope of the video analysis to study a transit event that involves the collision of multiple pedestrians.