Cul-de-Sacs, Connectivity, and the Hidden Cost of Street Design

Episode Transcript

Mollie (Host)
Welcome to {Brief}ly Speaking, the SEH podcast that tackles big topics in architecture, engineering, and construction with quick expert insights. No fluff, just the essentials. Let's dive in. Whether you realize it or not, the streets in your neighborhood shape almost every trip you take. They determine how easily you can walk to a park, bike to a school, reach nearby businesses, or simply get from one place to another. Cul-de-sacs, looping subdivisions, and disconnected neighborhood layouts have defined suburban growth for decades. They're often marketed as quieter, safer, and more peaceful. But they can also increase travel distances, limit connectivity, strain emergency access, and make even short trips dependent on a car. Today, we're unpacking how street network design impacts walkability, transportation efficiency, public health, and long-term community development, and why more engineers and planners are rethinking the disconnected suburban model. Joining me today is Randy Jenniges, a professional engineer, SEH principal, member of our board of directors, and our director of land development. Randy has spent his career helping communities and developers plan successful projects ranging from 40-acre developments to master planned communities exceeding 1000 acres. His experience gives him a unique perspective on how neighborhood design decisions impact both residents and long-term development success. So Randy, welcome to Briefly Speaking.

Randy (Guest)
Well, thank you, Mollie. I'm happy to be here today. I appreciate it.

Mollie (Host)
So let's kind of start with some basics here, Randy. Why should developers, communities, and residents care about something as simple as a street layout?

Randy (Guest)
Well, I think it goes back to kind of who the users are, right? And so who are the users? They're the people who buy the lots or build the homes, who live in the neighborhoods, right? They're the ultimate users. We have city officials, we have developers, we have engineers, but at the end of the day, who's using it are the people who live there. And so, the ultimate goal is to build development so that they feel good. It needs to be a great feeling of place. And people in development, people vote with their checkbooks, and they buy places where they want to live.

Mollie (Host)
That makes sense. And so we kind of talked about this in the intro there, but cul-de-sacs kind of became a dominant pattern for design. What problems were they originally trying to solve? Why did they come about?

Randy (Guest)
Yeah, so interesting fact. Back in 1936, the Federal Housing Administration officially gave cul-de-sacs the stamp of approval, if you will. And what they're really trying to do is move away from the traditional grid system, and they're trying to embrace more quiet, looping street type of systems. So moving away from grid systems, having more tools in the toolbox to be able to have more friendly developments.

Mollie (Host)
And they definitely hit that, right? They are quieter; the streets are quieter; people aren't zooming down the straight lines. But on the flip side of that, today we're hearing more and more about connectivity and walkability. So what are planners and developers seeing that is causing them to maybe rethink some of those layouts?

Randy (Guest)
Yeah, I think with cul-de-sac design, it definitely offers some really nice advantages. And then as you're alluding to, there's some disadvantages as well. And so I think the word moderation is probably the key to cul-de-sacs, that there's a magic point where using them in certain circumstances works really, really well. And using them in other circumstances, or too many, is a negative effect. And so there's a lot of different kind of ways to do that with topography and things like that. But I think that's the general answer with cul-de-sacs that it makes sense in some circumstances and some others they don't. And some cities, you know, have really good ordinances when it comes to cul-de-sacs, their standards regarding links and various sizes and things like that and how many can use on various developments. And others have a little bit different stance on that, but topography really plays a large role in it as well.

Mollie (Host)
Okay, good to know. And so now one more thing about walkability here is it's more than just sidewalks. Talk to me a little bit about why that is, what is walkability?

Randy (Guest)
Yeah, so walkability, the best way I can explain walkability is actually a personal experience. You know, my daughter has a friend who lives in the very next neighborhood next to us, and we're literally 300 to 400 feet apart from houses, but yet it literally is a mile for her to walk or to drive all the way around. That's two different developments, two different neighborhoods, poor walkability between the two neighborhoods. So walkability in my opinion, a lot of people, planners opinion is really the ability to get from neighborhood to neighborhood or development to development. It's not just, you know, the sidewalk along the street. While, sometimes that's important. Can we create connectivity between those two and create more neighborhoods and connect them up? If I could just extend this a little bit further, when you use cul-de-sacs, that can close off certain areas because it is the end of a street. And so I think there are ways to address the connection, especially with trails or sidewalks. A lot of times what we will do is we'll carry a trail from the center of a cul-de-sac to another center of cul-de-sac, going through the neighborhood areas. And so you can literally connect up the cul-de-sacs with neighborhoods. And there's a lot of aesthetic, really nice ways to do that.

Mollie (Host)
Okay, so there are some options to enhance that walkability connectivity while still keeping the benefits of a cul-de-sac too.

Randy (Guest)
Exactly.

Mollie (Host)
Now, when neighborhoods do rely on cul-de-sacs or some of those termed disconnected street systems, what impact does that have on the way that people move throughout the community as a whole?

Randy (Guest)
Yeah, so when you use cul-de-sacs in a wrong way, there can be longer drive times, if you will, within the development or getting to certain cul-de-sacs, that sort of thing. But you almost have to go back to why do people like cul-de-sacs? People like cul-de-sacs because there's less traffic, right? And they kind of have this feeling of place. And they have their own little neighborhood, if you will. I hear a lot of cul-de-sac block parties and things like that, and my own neighborhood has one of those. And our neighbors have a little party that they invite us to, even though we're not part of the cul-de-sac club. And so they really get their kind of little niche neighborhoods going on. But at the same time, you're right that there is some drivability. There's some timing aspects to it, but I think if you use those correctly and limit kind of the lengths of those cul-de-sacs, a lot of cities have maximum lengths of cul-de-sacs for safety concerns or just kind of number of homes on each cul-de-sac. I think some of those work well.

Mollie (Host)
Now you wear a lot of hats. I said that in our intro here, but we're going to put on your land development hat, which I know is one of your favorites. From that perspective, what are the economic impacts of connected versus disconnected street networks?

Randy (Guest)
Yeah, so how we really view it is really about efficiency. And yes, land development is one of my favorite topics. It's what we do and I've been doing it a very long time in a multitude of different states. We do basically efficiency analysis on the streets. And on residential developments, we like to be about 85% efficient or greater. We actually measure it. We measure the efficiency of the streets within a development and determine the type of efficiency. And if we're less than that, we have more work to do and we have better layouts we can come up with. And cul-de-sacs is just one of those tools that we use to accomplish various either density or and it may sound weird because it is the end of a road, but oftentimes we will get better connectivity using a few cul-de-sacs in various areas. All the developments that we do now, you're dealt with a piece of land that you're given. Not all land is perfect. In fact, the more we develop, the harder the land gets to develop, right? Because the easy stuff is taken up and all you have left is the hard stuff. And so you need these different tools to be able to develop that land. You're using everything you have to, you know, number one, make it efficient, get an ROI for the developer, and yet get a really nice kind of neighborhood.

Mollie (Host)
Okay. And now continuing on this same land developer hat trend here, when you're designing a new neighborhood, if a community comes to you and says, Randy, I have a plot for development. What questions do you ask or conversations do you have in that initial kind of meeting to determine whether a cul-de-sac belongs in the plan or not?

Randy (Guest)
Yeah, so the first questions we typically ask of our developer friends is what kind of market are we on? What type of lot? There's many different lot sizes and markets. You know, are we looking at, you know, the entry level housing type or, and it's really determined a lot widths, things like that. Or are we going for more of a higher-end type product? We have some products out there that the lots are selling for $600 to $800,000 a lot. Well, those lots are two completely different lot types. And so you have different concept layouts and networking done within those, right? And so it's kind of like going to a store. Are you go into an upper-level store and the feel that you get there, or are you going to just, you know, pick up something at a gas station, right? Those are two completely different feels. And so, you know, neighborhoods and developments work that way as well, with the different product types out there. So the first question has got to be product type. The second part is really about city ordinances and matching the product types and the network to the city ordinances. And so it's kind of like this chair with several legs of the stool. Just gotta match up all those legs of this stool properly to, I guess, build the chair.

Mollie (Host)
I like that. I like your example of the two different stores there where you're still purchasing something, but the quality or like the high-endness of it differs.

Randy (Guest)
Are you are you going to a car dealership and buying a Ferrari or are you going to a car dealership and buying, you know, a Fiat? Nothing wrong with either one of them, but it's just a completely different experience and different markets.

Mollie (Host)
And I think it's good to have that conversation at the beginning because some communities don't want a Ferrari. Some communities, they just need, the truck with the crank windows there. So it's good to have that and get on the same page with it so they're getting what they want and what they need.

Randy (Guest)
And really just to continue on that, you know, affordable housing is top of mind for almost every community we work with. You know, with inflation that has taken place, affordability is a true challenge for folks and, you know, new families entering the housing market and that sort of thing. And so you really need all these tools that you can try to hit that type of affordability, different levels.

Mollie (Host)
Yeah, exactly. So now beyond the individual neighborhood, we're gonna think wider here. How do development decisions around street connectivity shape the broader community? So from emergency services and school access to infrastructure maintenance and future development opportunities.

Randy (Guest)
Yeah, so I think from a number of different perspectives, connectivity is part of it. I think there's some general standards in a lot of communities where you reach over you know, 40 lots, then you should have secondary access, you know, for emergency access and things like that. Really good, good standards in place. But I think it matters for utilities as well because you're connecting up, you know, the utility backbone of the city is basically through developments in some of these residential development areas. Yes, they have main lines going through some of the main roads and things like that, but a lot of them use this skeleton system throughout the developments as well that most people aren't aware of that, you know, a lot of it is built upon one another where one development builds, it extends out water and sanitary sewer and the next development builds next to it and it builds on that and extends out sanitary, water, whatever. And so these are just as cities grow and continue to expand, that's just kind of how the system works and connectivity, you know, through the street system or utility system or trails. And then the last one is really stormwater. Stormwater really doesn't care which development it rains on and which way. Water only cares about going downhill. And so it really doesn't like have boundaries to that. And so you really have to pay attention to, you know, those watersheds across those specific areas and how you deal with them on specific projects.

Mollie (Host)
Yeah, that all makes sense. And now, Randy, you work with a wide range of developments, small to very large. Are there some examples of communities or development trends that you think are kind of getting this balance right today?

Randy (Guest)
Yeah, there's actually a lot of them out there. I think the communities, and I'll pick on cities for a little bit, the cities that allow, we call it planned unit development across many areas, they allow planned unit development, so they're going outside of their normal code, whether it's an R1 or R2 code and kind of allowing for more, I'll call it adventurous development. You know, I think those can be some serious winners. There's some give and takes on both the city side and development side where the developer gets maybe density or some other, you know, thing. And then the city gets, you know, something else in return, like, you know, more trails or more linear parks or, you know, something else. And there's just an automatic win-win. And when that happens, then the people who live there win, right? So you have three winners out of all of it. So I think that's a pretty good trend that's taking place a lot, especially with master plan communities that take place. Not saying standard zoning isn't workable. I think that's common in many areas and can work, but I think sometimes those rigid standards kind of restrict the creativity that, you know, the planners and engineers and the developers can have on projects to make them better.

Mollie (Host)
So now looking ahead, how do you see changing resident expectations influencing kind of the next generation of neighborhood design?

Randy (Guest)
It'll be interesting to see what takes place, but just for the last five to 10 years, I'll call it. I think as we went through COVID, people working from home, I think where they choose to live, you know, they're kind of more of a lifestyle moves that we've seen take place. And so kind of the migration pattern that has taken place over the five, 10 years is really quite prevalent. And they demand, you know, different things. The first question that I talked to someone who just lived in the neighborhood and the first question they have is what kind of internet connection do we have here, right? They expect water, they expect sanitary sewer, and they expect streets and all these things. But can I work from home? Is really the message. And you know, the other thing we're seeing a lot is different needs for dogs and pets. So more linear parks, more walkability. That's always been a topic, but boy, that's really getting pushed. It's almost a requirement in some of these areas depending on the market. If you go to entry-level homes, you know, it's really both that entry point, the cost entry point. And so we're seeing more narrower-width lots. Because the width of the lot really determines the cost of the overall development. It's a direct relationship to density and overall development. And so we're seeing some changes there. I'm seeing some new product types from the national home builders that we work with try to reach a certain entry point on a cost perspective to hit that first-time homebuyer kind of situation. So, you know, I could go on and on. I'm seeing amenity sites in the southern states that are just absolutely gorgeous and beautiful. You know, these gated communities with pools and pickleball courts and trails around lakes and all kinds of fun things like that. It really just depends on the area and the market and that sort of thing.

Mollie (Host)
Yeah, the needs and wants are definitely changing, which I'm sure makes your job a little bit more fun getting to design some of those more high-end areas versus just the square streetscapes.

Randy (Guest)
Right, right. And that doesn't mean that entry-level layouts can't be cool, right? And so we can still create either a curvilinear street design or cul-de-sacs and things like that, still get those densities. I think we should bring it upon a challenge to ourselves that that doesn't mean that there's a trade-off to entry-level home layouts.

Mollie (Host)
That's a great point. Well, as we've heard today, every street tells a story about the priorities behind a development. The choices made during planning don't just influence traffic; they shape how people connect with their neighborhoods, how communities grow, and how infrastructure performs for decades to come. A big thanks to Randy here for showing us how thoughtful street design can balance development goals with long-term community success. And thanks to everyone listening to {Brief}ly Speaking. Be sure to subscribe so you don't miss future conversations about the ideas and innovations shaping the places that we call home. Thank you.