During the Pamplona, Spain, "Running of the Bulls" you won't need all of the ambulances that are placed along the route, so how do event organizers know where they should be? Statistics helps know.
Experts have studied the bull runs of the last six years (a total of 48 races) in order to identify the risks that exist. As you might anticipate, absent an extraordinary event, like a terrorist attack or alien invasion, the risk to one set, the runners and the bulls, are the bulls themselves, the runners and the route. Runners may incur slight injuries such a falls, scratches or breakages, or even being gored. The bulls can suffer physical consequences such as broken horns or hooves.