Do you know how speed limts are set? Ever hear of the 85th percentile?

This is a fascinating article by Anna Maria Barry-Jester titled, "Why The Rules Of The Road Aren’t Enough To Prevent People From Dying". This article explains from early on how pedestrians and cars interacted; cars, believe it or not, were once subordinate to pedestrians. That is very hard to imagine in today's world.

The excerpt below is near the beginning of the article and delves into the not-too-scientific method of how speed limits on roads are determined. The article states this is an old national standard (the 85th percentile) so would presume Florida's DOT also uses this method for speed limits in our Lake Worth state-owned roads, Dixie Hwy and Federal Hwy for example:

     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. [emphasis added] The NHTSA estimates a $277 billion annual price tag 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.
     Here’s how speed limits are established in most states, according to Federal Highway Administration research: Traffic engineers conduct a study to measure the average speed motor vehicles move along a road. The speed limit is then set at the 85th percentile. From then on, 85 percent of drivers would be traveling under the speed limit and 15 percent would be breaking the law. Sometimes other factors are taken into consideration, but in most places, speed limits are largely determined by the speed most people feel safe traveling.

If you continue reading on in the article think you'll be interested in how "jaywalking" came to be.