Why The Rules Of The Road Aren’t Enough To Prevent People From Dying

By Anna Maria Barry-Jester, FiveThirtyEight

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How speed limits are set

In 2013, 32,719 people died in motor vehicle crashes in the United States, and 2.3 million were injured, according to the National Highway Traffic Safety Administration (NHTSA). Those numbers were down from the previous year, but motor vehicle crashes remain a leading cause of death, and speed is a leading cause of accidents. The NHTSA estimates a $277 billion annual price tag1 for those accidents, with an additional $594 billion for “harm from the loss of life and the pain and decreased quality of life due to injuries.”

Given the social and economic toll of speeding, one might assume that we set speed limits with careful calculations aimed at maximizing safety. But that’s not exactly how it works, and a history of questionable applications of data is partly to blame.
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http://fivethirtyeight.com/features/why-the-rules-of-the-road-arent-enough-to-prevent-people-from-dying/