Highway Death Math
Reuters has a breathless story entitled “Highway Deaths Hit 13-Year High in 2003.” It’s a rather poorly written series of one-sentence paragraphs with its lede buried several “paragraphs” in:
The number of U.S. traffic deaths rose nearly 1 percent in 2003 and reached a 13-year high at 43,220, the government reported on Wednesday.
It was the fifth straight year road deaths rose, although passenger car fatalities decreased. Sport utility vehicle deaths went up roughly 10 percent over 2002, with more than half of the victims in those crashes killed in rollovers. Motorcycle deaths also jumped.
The National Highway Traffic Safety Administration said preliminary figures showed 405 more highway deaths overall in 2003 than the previous year and the most since 1990 when 44,509 people were killed.
Despite the increase in the annual death count, the fatality rate per 100 million vehicle miles traveled remained constant at 1.5 deaths because more people were on the road. [Emphasis mine]
So, rather than “Highway Death Rate Unchanged,” the much more accurate headline, the story instead emphasizes the raw numbers. Given that the population is increasing and the number of miles is increasing, the greater number of fatalities is hardly surprising. Some other missing facts from the story:
- Did passenger car deaths decrease due to fewer miles driven in passenger cars, because of safety improvements, differential weather conditions, or what?
- How many miles are driven on motorcycles in the years compared?
- Is a 2002 SUV the same as a 2004 SUV? That is, are people gravitating toward the passenger car-style “SUVs” and away from the traditional variant based on a truck chassis?
- How many miles are driven in SUVs (of whatever type) in the years compared?
These stories have been around long enough that these questions should be obvious to reporters –and certainly their editors.