This story in Kansas City has a happy ending, but it begs the question: why was this neighborhood- and local business-serving street so unsafe to cross? And why did the people and non-profits in this area have to take matters into their own hands to make a change?
The answers to these questions lie in our outdated traffic rules and policy. When a road is being designed, engineers use criteria established in the 1940s to decide on the most effective design. And the “effectiveness” was based on measuring how quickly you could get from point A to point B. Simply put, the rules outlining how to best design a road are not in sync with what is best for communities.
An easy-to-identify enemy of making neighborhood streets safe for all users is the 85th percentile rule; this rule claims that the safe speed limit for a road is whatever 85% of users are driving at or below. Artificially raising or lowering speed limits could result in more crashes. Though this rule is not enforced by any federal agency, it is widely used to determine safe speed limits across the U.S.
I wouldn’t argue for the complete nixing of this rule. Instead, I would argue that under sensible road design, the rule could be used more effectively. Neighborhood streets, like those in Kansas City, are designed to create a false sense of security, and it makes users feel as though they can drive faster than what is safe. The 85th percentile rule has many disadvantages. It has been pointed to as the cause of gradually increasing operating speeds, and though it may work well for highways and roads, it is ineffective when implemented in residential areas. The rule is useful for something, though: it proves that our neighborhood streets are largely being designed in a way that is not safe for all users.