Best of 2020: Doing the Math on Roads, Cul-de-sacs, Drainageways, and More

We’ve been fortunate this year to publish a number of articles by people who are running the numbers in their cities and confronting head-on the absurd un-affordability of the North American development pattern. Something that makes me particularly hopeful is that not all of these analyses were done by folks you might call built environment professionals: planners, engineers, architects, etc. It’s possible—even vital—that laypeople realize they have access to everything they need to #DoTheMath in their own towns and cities. You don’t need to be a Level 20 Spreadsheet Wizard to discover that your city is going broke with every new infrastructure project that can’t possibly pay for itself. And, as powerful as they are, you don’t have to create Urban3-style value-per-acre maps to advocate for a better way to neighbors, the local media, or the city council. If you’re ready to #DoTheMath where you live, here are some resources that will help. In the meantime, check out these powerful case studies from the past year. — John Pattison, Content Manager


“I Did the Math on My Town’s Cul-de-Sacs. Here's What I Found,” by Dustin Shane

Image: Google Maps

Image: Google Maps

After mulling over our situation here in Gallatin, I decided to focus on the cul-de-sac. Why? Well, as a city that didn’t start growing in earnest until the automobile age, we have plenty of them. And second, I’d read [Chuck Marohn’s] seminal article about the cul-de-sac. It made perfect sense. If a cul-de-sac is stripped to its essentials and brought to the bar of the balance sheet, it has nowhere to escape. It can’t offer the excuse, like most of our wide, low-density commercial roads, that it provides network effects beyond its immediate vicinity. It exists for one purpose and one purpose only: to provide access to the homes built around it. That’s why Chuck identified it as the perfect candidate for a fiscal “interrogation” and why I’m following in his footsteps.

Read the full article.


“This is why we need to #DoTheMath, even on ‘small’ projects.” by Jared Wright

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When I received a letter saying that the little neighborhood street I live on was scheduled for some improvements, I wasn’t surprised, as other streets in the area were being resurfaced. The stated intent of the project is to upgrade the street to the City Standard. However, as I read further, something jumped off the page at me: $2.1 million.

While it is critical to maintain what you have, I wanted to use this project to point out that doing it requires restraint as well. As we've seen many times on Strong Towns, "maintain" can quickly become "upgrade" in the presence of available money. Especially, as is often the case, when that money is borrowed.

Read the full article.


“It’s All Downhill from Here,” by Michel Durand-Wood

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So the really interesting thing to note here is that while it looks mostly profitable in its early years, around year 20-25 the graph turns into a sketch of the toboggan hill my kids built out front. That’s when all that “free” infrastructure the developers built for us starts needing replacement. And we realize that we’ve built a neighborhood that can’t support its own infrastructure.

Not to worry! We can just build another! After all, today’s Waverley West is just tomorrow’s Southdale. Setting aside the fact that that is the very definition of a Ponzi scheme, let’s just put that on a graph for fun…

Read the full article.


“Land Use and the Cobra Effect,” by David Skuodas

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The channel was built this way to allow for a few extra commercial buildings. I looked into how much this property is worth, and with a little math was able to figure out how much funding the District collects from this property each year.  We get around $270 in total revenue from this property, around $100 of that is for maintenance. I looked at what it would cost to fully replace all of this concrete someday and determined it would take over 17,000 years for us to build up enough funding from this property to pay to replace the channel infrastructure. I am not making that up.

Make no mistake, the channel was configured in this way to benefit this particular property. We’ve lost all ecological and recreational functions, and it will be a serious financial burden for the entire community.

Read the full article.


“The Solvent City: What Does It Look Like?” by Dustin Shane

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After joining the Strong Towns movement, my first thought as a planner was, how do I translate Strong Towns principles and tools into workable formulas for my town, Gallatin, Tennessee? I could talk about things like the Growth Ponzi Scheme, but I knew that without some hard, localized data to back it up, people probably wouldn’t take the message seriously.

My last article for Strong Towns took Chuck’s Analyzing the Cul-de-Sac article and applied it to twelve cul-de-sacs in my town. Predictably, I found that none of them generated enough tax revenue to pay for their own maintenance and replacement. In this article I’d like to take a more macro view, but using the same ideas and data for the most part—and coming to the same conclusions, as I’m sure you’re expecting.

Read the full article.