www.lesswrong.com/posts/7XbcDaeigMaxW43EB/how-to-avoid-dying-in-a-car-crash
1 correction found
75% of all crashes!
The linked FHWA statistic is being misread here: it says 75% of weather-related crashes occur on wet pavement, not 75% of all crashes.
Full reasoning
The article’s linked FHWA material does not say that three-quarters of all crashes involve wet pavement.
What the FHWA says is that 75 percent of weather-related vehicle crashes occur on wet pavement. That is a much narrower category than all crashes. The same FHWA research stream also reports that wet pavement accounts for a far smaller share of all crashes overall.
A contemporaneous FHWA-authored conference paper states both figures side by side: “Seventy-five percent of weather-related crashes occur on wet pavement” and “Of all vehicle crashes, 18 percent take place on wet pavement.” That directly contradicts the post’s claim that “75% of all crashes” involve wet pavement.
So the error is not that wet pavement is unimportant — it clearly is — but that the post dropped the crucial qualifier weather-related and turned a subset statistic into an all-crashes statistic.
2 sources
- Rain & Flooding - FHWA Road Weather Management
“Most weather-related crashes occur on wet pavement and during rainfall. Each year, 75 percent of weather-related vehicle crashes occur on wet pavement and 47 percent happen during rainfall.”
- 8.1 U.S. highway crashes in adverse road weather conditions
“Seventy-five percent of weather-related crashes occur on wet pavement and 47 percent happen during rainfall. Of all vehicle crashes, 18 percent take place on wet pavement and 12 percent occur during rainfall.”