Red Light, Green Light, No Insight

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In our transportation system, we’ve created what I call a “safety theater” based on an outdated understanding and application of transportation engineering. Those outdated concepts keep us in a system that costs us way more than any of us are willing to pay—not just in dollars, but in time, safety, and quality of life.

And to be clear, it is literally bankrupting our cities.

Some will want to point the finger at corruption as the cause of our financial woes. But corruption isn’t generally the cause of insolvency, it’s usually a symptom of it:

“Eventually, we reach the condition of Detroit. […] Money is allocated for fixing things like the cracked floor at the fire hall, but nobody knows where it went. The floor is never fixed. City hall is distant and clearly corrupt, but who among decent people would step up and try to fix it?”

— from “We are all Detroit,“ Strong Towns

Sound familiar?

But we don’t have to accept it. There is a lot of work to be done, including getting to the bottom of any potential financial mismanagement in the Transportation Department. However, concurrently, we must also attack the root of the problem. And one of the places we must start is our transportation system.

I recently heard Beth Osborne, Director of Transportation for America, compare street design to house design. We would never ask engineers to design our homes, she said. The homeowner decides what they want for their home, and with the help of an architect, a banker, an engineer, and a contractor, among others, will come up with a design that suits their needs. The engineer’s part is to make sure it is structurally sound. But the homeowner is the leader of the design process, nothing happens without their say-so.

Similarly, we shouldn’t let engineers design our streets. Yes, they should be involved as part of the team, but we, the community, are in charge of the process. Is this to be a neighborhood street with children playing hockey? A thriving shopping district? We decide what our needs are, and that determines what the street needs to look like. The engineers contribute by providing technical guidance—like determining pavement thickness, for example—to meet those needs.

Just like software engineers don’t design the user interface of an app, so traffic engineers should not design the user interface of our city.

Because when we hand the entire process to engineers, from A to Z, we shouldn’t be surprised that the values of their profession quickly override the values of the public. Done long enough, we start to wrongly believe that their values are our values.

The standard engineer’s approach prioritizes high vehicle speeds over everything else, no matter what. But we now realize that there is a place for high vehicle speeds, and a place for slow vehicle speeds. Welcome to the new paradigm.

And when we unchain ourselves from those old shackles, we can come up with approaches to transportation for our city that are actually safer. Approaches that are cheaper. Approaches that boost property values, stimulate economic activity, and create local wealth. Approaches that were impossible under the old assumptions.

Let’s use traffic signals as an example, since that’s what started all of this. When we recognize that some places are for high speeds, and some are for slow speeds, we come to the inevitable conclusion that traffic signals shouldn’t even exist. I know that sounds crazy, but think about it.

In places for high speeds, intersections just slow us down, thus wasting the significant investment we’ve made in the infrastructure. If there are no intersections, there is no need for traffic signals. The right approach in these places is to minimize intersections and access points, and replace the remaining ones with interchanges, not traffic signals. It’s the approach we’ve taken with the North Perimeter Hwy, and even though some residents are complaining, it is the correct approach to maximizing safety, as well as the return on our infrastructure investment in this kind of place.

However, in places for slow speeds, places where people walk, work, live, shop, play, and go to school, places where we have or want human activity, vehicle speeds should be so low that traffic signals are unnecessary.

But you don’t need to take my word for it, here’s professional engineer Chuck Marohn from his book, Confessions of a Recovering Engineer:

“I find traffic signals maddening, perhaps the most casual waste of time and resources to come out of the practice of civil engineering. If I could, I would eliminate every traffic signal in every city in North America; just rip them out and throw them in a landfill.


Traffic signals are only necessary because of the speed of traffic. If traffic moved slower, say a neighborhood-friendly speed of 10 or 15 mph, traffic signals would become largely unnecessary.

Here is the maddening part: If traffic could flow freely at neighborhood speeds with no traffic signals and red lights to impede it, if people could navigate along city streets at 10 to 15 mph — speeds that might result in a fender bender but rarely a fatality or serious injury — most people would arrive at their destination quicker.”

— From Confessions of a Recovering Engineer, by Charles L. Marohn, Jr.

Yeah, I know. Think about it, there are no traffic signals inside a Costco parking lot, and yet, there is a safe mingling of vehicles, people, and shopping carts. Using this approach in our neighborhoods is not only safer, it’s cheaper, and creates more economic value, too. The best of all worlds.

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