An acquaintance of mine in the insurance industry shared with me that 18 service vans would crash this month in his city. How did he know that? It's history.
Using their actuary tables, insurance companies can predict when and if service vans will crash and burn. They know what days most of them will crash; how rain, snow, and sun will affect this number; how many injuries will result from those accidents; and how many fatalities will happen. They know this all from studying what's happened in the past.