Traffic Engineers’ Epic Fail

The essay below, which we're including in our annual review of best content from the year (see all of it here) is striking because of its concise and simple message, a message we at Strong Towns have been shouting from the rooftops for almost a decade: Most streets are designed in a way that induces dangerously fast driving (no matter the posted speed limit) and the result is tens of thousands of deaths every year — many of those children. As an engineer, Jon Larsen calls out his fellow street design professionals and demands that they change their tact immediately. It's a powerful and important message that every city needs to hear.  - Rachel Quednau


This last week, a junior high student was hit and killed in Syracuse, Utah while crossing the street at a crosswalk in front of his junior high school.

This story hits home to me for two reasons. First, I have a son this same age who I absolutely adore, and I can’t imagine how bad it would hurt to lose him, especially in such a senseless way. Second, I believe that my profession (traffic engineering) has failed this young man, his family, his school, his community, and hundreds like them throughout this state and region. There’s no other way to put it: This is failure. Epic failure. Someday as a profession and as a society, we will stop giving lip service to the concept of “Zero Fatalities” and make real change. I’m hoping it’s sooner than later.

Let’s take a look specifically at how we failed in this situation.

Source: Google Earth

There is an elementary school and a junior high school across the street from each other. This street should be one of the safest in the city. But it isn’t.

A quick physics lesson: The force of impact from a car increases quadratically with speed. This means that doubling the speed quadruples the force of the impact. The statistics bear this out. A 40 mph street is about 5 times more deadly than at 20 mph street (see chart below).  

Source: FHWA

Considering that kids are coming and going from these schools throughout the day due to extracurricular activities, etc., you would think that the permanent speed limit would be 20 mph. Maybe 25 mph. Nope. The speed limit on this street is 40 mph. Refer again to the chart as to why 40 mph is so much more dangerous than 20 mph.

It gets worse. Some years ago, for my master’s project, I looked at the impact of speed limits on the speed that people actually drive. In nearly every case, there was no correlation. Drivers choose their speed (without really even thinking about it) based on the design of the street, not the posted speed limit. The street separating these two schools in Syracuse was designed for speed, which means it was designed to kill.

I have no doubt that the driver who killed this young man meant no harm, but made a mistake by either driving too fast, not paying enough attention, or both. I have no doubt that this young man is a good kid who tries to look both ways and be cautious when crossing the street, but perhaps wasn’t cautious enough. Obviously, human error was at play. But the consequence for minor lapses in judgment shouldn’t be death.

The street between these schools. (Source: Google Earth)

This street is long, straight, and wide. Everything about this design tells the driver, “Go ahead, drive fast. It will be OK.” Meanwhile, children are crossing at a marked crosswalk, lulled into a false sense of security. As a human being, and as a teenage boy in particular, the young man who was killed here was challenged in judging the speed of oncoming cars and the risk they pose to his safety. We set these kids up for failure in a big way, and we do this again and again all over the region and the country.

What’s the solution? There are numerous other “traffic calming” treatments that could be added to this street, none of which really cost that much, especially when compared to the precious young lives that are at stake. If we can afford to add new streets and highways, we can afford to fix our existing streets first. You can start with a temporary implementation in your city to spark people's imagination.

That said, the best, most lasting solution is to narrow the street until it’s uncomfortable to drive fast. There have been some previous Strong Towns articles on the virtues of narrow streets. The benefits go well beyond safety, as articulated in “Narrow Streets do More with Less” and “Some Thoughts on Narrow Streets.

I’m calling out my entire profession today. This is a systemic issue, a tragic case of groupthink gone wrong. The change needs to come from the highest levels of leadership all the way down the chain. Just as important, change needs to come from elected officials who should make it crystal clear that safety is more important than speed. The change needs to come from an educated public that understands this tradeoff and is OK with it. Until that happens, the tragedies will continue.


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About the author

Jon Larsen is a professional engineer in the state of Utah. He spent the first half of his career in the private sector as a traffic engineering consultant and currently works in the public sector doing travel demand forecasting. His specialties and interests lie in understanding the transportation/land use interaction, and in creating great places where communities can thrive. Jon is the chair of the board for the Congress for the New Urbanism (CNU) Utah Chapter. He has been a Strong Towns member since 2013.

Jon Larsen