The Harvard Business Review has a piece this month on research by Lawrence Frank, Bombardier Chair in Sustainable Transportation at the University of British Columbia, on the effects of cul-de-sacs in neighborhoods in King County, Washington. He found that residents in areas with the most interconnected streets travel 26% fewer miles by automobile than those in areas with many cul-de-sacs. Meanwhile, recent studies by Frank and others show that the higher a neighborhood’s overall walkability, the greater the amount of walking and biking— which means a drop in per capita air pollution, fuel use, and body mass index.[SButtonZ button="digg"]
The theory behind cul-de-sacs was that they lessened traffic, since they change the primary function of local streets — rather than offering a way to get anywhere, now they simply provide access to private residences. The problem is that this design inherently encourages car use, even for the shortest trips. It also limits the growth of communities and transportation options. Consider the above maps of one-kilometer walks in two different Seattle suburbs — the first, in Woodinville, is all cul-de-sacs that result in a disconnected jumble of streets with no walking or bike paths, while the second, in Ballard, offers an interconnected network of streets that provide easy access to shopping, parks, and other destinations. The argument that cul-de-sacs increase safety because they limit traffic is also misguided — the more empty and desolate a suburban (and often affluent) street is, the more likely crime is to occur. Also, it’s much harder for emergency vehicles to reach these homes if they’re sequestered in the belly of a web of disconnected dead-ends.
As more and more direct evidence piles up that these dead-end developments are doing no one any good, the cul-de-sac tides are beginning to change: Last year, the Virginia legislature passed a law limiting cul-de-sacs in future developments. And if other states see the benefits for VA – more efficient streets that are cheaper to maintain, as well as other savings from not having to widen arterial roads that otherwise were overburdened by cul-de-sacs — perhaps they’ll follow suit.
Image: Urban Design 4 Health
It seems, as I read these comments, that most people defend the lifestyle they know. I wonder if they forget the reason for the village that was there before the city grew? Do they live and work within a one mile radius of where they work, shop and play?
I suspect that most of the comments defending the status quo are from people who are totally dependent on cheap energy and believe that everyone should have a car and huge freeways.
Living in the city in a grid-system didn’t stop us from playing out in the street. We did it all the time.
As for Bob’s recent comment, I’d like to point out that the trains in DC and Minneapolis are not “full of smelly, unwashed people”, but instead are filled with clean, business professionals…especially at rush hour.
Robert: not everyone. If the smelly, unwashed masses have easy access to houses right next to where proper, cultivated people live, then the world will end.
[...] particular, the two areas studied appear to differ on much more than just their street layout. As one commenter [...]
[...] How Cul-de-sacs are Killing Your Community – The Infrastructuralist. You know what I hate? Pretty much every neighborhood built after 1980. [...]
There are still some things left uncovered here. As a transit planner, I’ve worked in Edmonton, Alberta, which in the late-1970′s did believe in maintaining walk distances to transit stops, whether or not an area had cul-de-sacs. Much of this was accomplished with “U-lots” so labeled on the plans, which were utility corridors that also shortened the runs for utilities into new subdivisions. Children could play in the U-lots and they usually were within view of one to three residences.
We also found that the design of cul-de-sacs and P-loops could be varied to cut walk distances without affecting buyers’ preferences or even the costs to developers (except that they couldn’t save money by using their scale drawing over and over again).
In the Denver metro area, we have all types of street layouts to serve, but the costliest and least productive are areas with cul-de-sacs off of cul-de-sacs, or loops that face away from collector roads. Even if the price of gasoline doubled overnight, these areas would only warrant what they would consider to be mediocre service. Some of these areas are justified by being in the foothills of the Rockies, but some of them appear to have been built on the theory that all the good things mentioned previously could be magnified by designing more complex streets.
The entire discussion about how safe and quiet cul-de-sacs are is offset by the volume of traffic converging on the stem of these neighborhoods out onto collectors or arterials. At 7:10 a.m., there is noticeable traffic stacking up, idling, to get out onto the (unsignalized) road. Late at night, motorists headed to the elite inner cul-de-sacs can take the big curves at the entrances at higher speeds than they can when the shortcut through my inner city neighborhood grid.
Any form of street pattern carried to extremes will create problems.
It may be true as far as transportation and conserving energy is concerned. But, safety is very important. I live in a neighborhood that has mostly straight roads and with people driving at crazy sppeds, it is so dangerous to let kids to play in the front yards. I have always envied houses on cul-de-sacs with kids playing basketball, bikes, etc. safely…
One key reason that there are so many culs de sac is that they’re cheaper and easier to build than connective streets, and consume less land. This is especially true if a new subdivision is developed on a small parcel. Look at a map of a typical cul de sac subdivision: the lot depths are the same as those in gridded neighborhoods, and the street system is essentially a grid with all of the nonessential links removed so that houses can be built on the land instead.
A cul de sac layout maximizes profit for the developer, and that’s why it’s so prevalent.
The Cul-de Sacs in my area are kind of getting out of control in Virginia such as there is this one new nighborhood they are putting in with $500,000 houses. There are only two openings in it that are four lanes wide and you simply can’t drive stright down it instead you will have a street go for a 100 feet dead end then have a Cul de Sac break off of it and to add to the mayhem of it all the streets have the same name only with the last name street drive or view.
There was a lovely town in Pennsyvinia called Carlise Pennsyvinia it wasn’t a dense city and the houses where more farther spaced then in some of these modern cookie cutter cul de sac subdivisons. It was a classic grid shaped town where it had an old small local train station in the center of it but everything was linked up by a massive grid of old sidewalks that where in great shape. You walk though this place and go at least two or three miles one way on the sidewalks along nice tree lined streets that didn’t dead end and the traffic was kept undercontrol. This place would make a great example of what the future should be about not this souless sprawl of Cul De Sacs dumping traffic on to monster four and six lane wide highways. Carlise’s street grid was very nice and many of the sidewalks had date markers on them from the 1950′s and 1940′s but they where in good shape and the street trees where at least 50 to 80 years old covering up the sun from hitting the cement. I think there needs to be more places like this vs more Cul de Sacs. What I liked about the place is that you didn’t need to drive around and get into a car and go park it and sit at all the traffic lights and compet with hords of fat cell phone trolls driving SUV’s.
[...] How Cul-de-Sacs Are Killing Your Community. [...]
A major flaw in this study that no one yet has pointed out is that correlation (grid pattern and fewer vehicle miles traveled) does not equal causation (grid pattern produces fewer vehicle miles traveled). Is it not possible that people who prefer to drive less end up in gridded neighborhoods, and people who prefer to drive more choose to live in cul-de-sacs? In other words, people being observed may self-select into these different neighborhoods.
It might be like a Cul De sacs are a mononpoly in that you try to move it a place do to a job opening but you want to movie into a grid neighborhood with grid streets and sidewalks but the only places out there to buy are Cul De sacs. So even though you want to live in a grid street the only thing there is Cul De sacs so the cul de sac has a monopoly.
On the other hand, people generally prefer to live in cul-de-sacs vs. on thru streets. If the motive behind city planning is a higher population density perhaps cul-de-sacs don’t make sense. But if neighborhood desirability is a major factor maybe they do.
Jbemory, do you like on a street grid? How do you know a cul-de-sac is soooo much safer?
I grew up in a small, pre-WWII town outside of Pittsburgh. The town was on a grid. We had an alleyway that we would play in without having to play in tons of traffic on the front streets. Everyone knows each other. We basically had all the perks described about cul-de-sacs while being able to walk and bike all over more easily. (also women could walk around town for exercize and all, or people would jog or watever – another pair of eyes that would be lacking on a cul-de-sac. Just sayin.)
And don’t forget that these neighborhoods need to cater to more than just children – being in a more dense and walkable town gave us a lot of options for things to do neraby but away from home during our teen years, and allowed for bus service as well. All without having to ask someone’s mum to drive us and pick us up.
I agree that a good solution is a (more or less) grid of streets with are cyclable in all directions but no through traffic is possible for cars.
At risk of playing devil’s advocate, is the non-walkability really inherent to the cul-de-sac system? Why couldn’t a developer combine the cul-de-sacs with trails providing shortcuts to pedestrians and bicyclists?
Cul-de-sacs are also energy-inefficient. You more often than not have to travel 1-2 kms in the wrong direction — at both ends of each direction of travel — just to reach the arterials.
They also create disorientation for those who are ‘visitors’ and can’t cope with the deviations from right-angle grid patterns.
But they serve a good purpose: cutting down on through traffic by cars and trucks. But they do this by pretty much eliminating traffic of a lighter nature: walking, cycling, roller-blading, boarding, which are not undesirable.
The way to bring back the grid without getting the motor traffic back is to borrow the idea of Duany, et. al.: ‘yield streets. These put two-way traffic on streets that are only wide enough for one-way traffic (usually by allowing parking on both sides or regular streets, or being built from day-one as a narrow street). In this system, motorists have to slow down to pass each other or to pass cyclists, or even to have to turn into a laneway or parking spot to allow the motorist from the other direction to pass. But cyclists don’t have to do this, since they are narrower. This slows the traffic enough to make it safer, and to discourage use of motor vehicles there at all. Slower traffic allows the human-powered travelers to mix with motorists, rather than be relegated to the gutters.
Ottawa, Canada
I had no idea that so much could be said on the topic. wow.
I noice with the Cul De sacs is that if the main road leading out of the place is blocked by a acident or something your day is shot. In that it’s the only way out and no way around it. But if you have a grid you can easly go around it. It is easier to go around something in the City of Richomd then it is the suburbs.
I live on a cul-de-sac and I am spoiled by it. I can sit at the edge of the circle to warn about incoming cars, etc. and my small kids can ride their bikes, etc without the fear of getting run over. I can’t imagine moving to a through-street until my kids are older.
I hear again and again how great culs-de-sac are “for the kids.” I never hear about how great they are for the grown-ups. Maybe they’re just great for people who never did grow up, or maybe they’re great at keeping people trapped in childhood.
I would go out of my freaking mind if I had to live in a cul-de-sac. I’d feel like I was in a cage. I want to live in a community, not a Habitrail, where the tubes dictate where I get to go.
And I don’t want my kids growing up without developing some alertness to risks in their environment. I want them to know, both consciously and subconsciously, that traffic comes from more than one direction, and that strangers are normal.
[...] Found this here: [...]
Ballard? Isn’t Ballart part of the city of the Seattle? Since when was it a suburb?
The benefits and drawbacks of cul-de-sacs depend on what your view of an ideal community is. There are good, in my view, arguments for and against them and what a larger community’s over-all planning goals are determine whether or not cul-de-sacs should be permitted. Cul-de-sacs actually are a little community in and of themselves. Neighbors living in the sac are more likely to interact that those living on straight line streets. What has led to the death of sense of community are the 2 garages (storage sheds) and 2 car parking lots built on the front of houses and the lack of front porches as a result. Porches are community meeting places. Do you ever see anyone in our modern burbs sitting on a front-of-the-house porch? People stay inside and out of sight because they don’t have a porch to sit on to watch their kids play or people walking around.
Another killer is the development of 4 lane interstate highways that led to the development of 6 and 8 lane interstate highways making it possible for people to live further and further from the city core. People who live 45 minute drives to and from their workplace have no time to socialize with their neighbors.
I think the model for urban development is found in the cities in Europe. There are no interstate highway systems that serve as conduits for commuters in and out of the city. There is no parking or parking is outrageously high. Severely limit those two things, multi-lane highways and cheap, accessible parking, and the cities fill up again and urban transportation will flourish.
I live near Berkeley where they have replaced cul-de-sacs with “traffic calming” This is where they plant a big tree or stick a permanent barricade smack in the middle of residential intersections so cars can’t go through. The first time one tries to cut through a neighborhood there’s a good chance they’ll hit one of these intersections and get dumped back onto the nearest through street. Several reasons this works better than cul-de-sacs:
*Cars can still go left or right so it’s not (usually) a dead end
*bikes and pedestrians can still go through just fine
*takes up less space and doesn’t require the road to be rebuilt
I hated the traffic calming at first but after a while you just get used to driving on the through streets rather than trying to cut through people’s neighborhoods. And it is true that I’ve seen people hold street parties with BBQ and kids running around right in the middle of the road in Berkeley, which wouldn’t be possible without traffic calming. That being said, now that I’m used to the way they do it here cul-de-sacs drive me insane. So often they are part of a ridiculous system of winding roads that doesn’t go anywhere…once parked my car on the wrong cul-de-sac in LA and it took me over an hour to get back to it! When you think about it, every street doesn’t need to be a dead end to reduce through-traffic, just enough twists that it’s more convenient to go three blocks out-of-the-way to the street that’s designed for traffic. It works for us in California!
it is not about cul-de-sacs, it is all about design. don’t be a fool. grid system just for robots
[...] grid (and its political effects) before. Other reactions on the walkshed study are available at Infrastructurist and Human [...]
If cul-de-sacs cut down on infrastructure that needs maintenance, then they can be a good thing.
[...] Unintended Consequences of Cul-de-sacs [Harvard Business Review] The Cul-de-Sac Ban [NYT Magazine] How Cul-de-Sacs Are Killing Your Community [Infastructurist] The Damaging Effect of Cul-de-sacs on Walkability [Seattle Transit Blog] Is the [...]
I used to deliver for King Soopers (until I broke my hand) & I can say from personal experience that Cul-de-sacs are a pain in the butt! One community builder thought it would be “cute” to have one in the shape of an “H”. Only 1 way in & out is via the the crossbar. The streets also have the same name & no differences i.e. E Cherry & W Cherry; but 1 street called Cherry. The only difference was in the minds of the residents.
I grew up on an anti cul-de-sac and moved with my family to a cul-de-sac in HS (and have lived in cities whenever I chose for myself), and it’s now in hindsight that I can look back and see the planning failure of a cul-de-sac.
In general, most houses in a new subdivision lie on the feeder streets while a select few get to be on the coveted cul-de-sac. Compared to the street I grew up on this is completely inefficient.
The “anti cul-de-sac” I grew up on was part of a fantastic residential grid of streets. The main streets had larger houses and deeper setbacks, while the bulk of the housing sat on cross streets with smaller setbacks. Most only went for three or four blocks so there was no end destination making them like a cul-de-sac in their traffic patterns. The upside was that each block had 30-40 houses with 2-3 larger houses on the “end cap” of the block. We frequently played in the streets since few non residents drove down the streets and those that did knew to drive slowly. Instead of riding my bike in circles on a cul-de-sac I had nearly a quarter mile to ride back and forth. Because it was part of the grid and not an isolated development there were also regular walkers from nearby blocks and was able to walk to school and nearby parks (and ride my bike to stores before I was technically allowed to).
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=10606&sll=37.0625,-95.677068&sspn=37.871902,78.837891&ie=UTF8&hq=&hnear=White+Plains,+Westchester,+New+York+10606&ll=41.010313,-73.765469&spn=0.008825,0.019248&t=h&z=16
There has also been interesting research on whether crime increases or falls in cul de sac compared with interlinked streets Colin Buchanan’s blog looks at this
http://colinbuchanan.wordpress.com/2010/04/13/is-there-a-link-between-design-and-crime/
Culs-de-sac don’t necessarily have to promote car use – after all, in a high density, mixed use context, with pedestrian walkways between culs-de-sacs, or even in a suburban context with park-and-rides along the arterials, the result can be considerably friendlier to transit, by causing the collection of people and traffic in one or more locations. This result presumably works best with a concentrated CBD area, unless someone comes up with a way to solve the “last mile” problem of transit access to distributed workplaces. The problem is that culs-de-sac are deployed in a random, dispersed fashion with low density, single-land-use characteristics, resulting in a situation unfriendly to transit and walking and pretty confusing to drive.
For the record, I grew up in quarter-acre-lot land, but not on a cul de sac. My neighborhood is mostly interconnected streets, although there is a cul-de-sac on one end of it and there are also some dead-end streets. There is a shopping center within walking distance, but the stores amount to bodegas and small shops, and it’s a small shopping center.
It has an unusual history for a suburban area, though, having been started by bodybuilders, expanded into a vacation cabin area, and then fleshed out into a full suburb with the houses that come along with it.
[...] with cul-de-sacs. For the love of infrastructure, I strongly encourage everyone to advocate for attractive, [...]
The plural of cul-de-sac is culs-de-sac, not cul-de-sacs. One would think the Harvard Business Review would know that.
sounds like its a matter of choice.
live where you want to and don’t live where you don’t.
obliviously money is ALWAYS the issue.
[...] in fact be safer than cul-de-sacs. Reporting on the same research by Frank, Melissa Lafsky adds inThe Infrastructurist, “the theory behind cul-de-sacs was that they lessened traffic, since they change the primary [...]
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“The way to bring back the grid without getting the motor traffic back is to borrow the idea of Duany, et. al.: ‘yield streets. These put two-way traffic on streets that are only wide enough for one-way traffic (usually by allowing parking on both sides or regular streets, or being built from day-one as a narrow street). In this system, motorists have to slow down to pass each other or to pass cyclists, or even to have to turn into a laneway or parking spot to allow the motorist from the other direction to pass. But cyclists don’t have to do this, since they are narrower. This slows the traffic enough to make it safer, and to discourage use of motor vehicles there at all. Slower traffic allows the human-powered travelers to mix with motorists, rather than be relegated to the gutters.”
—-
“I live near Berkeley where they have replaced cul-de-sacs with “traffic calming” This is where they plant a big tree or stick a permanent barricade smack in the middle of residential intersections so cars can’t go through. The first time one tries to cut through a neighborhood there’s a good chance they’ll hit one of these intersections and get dumped back onto the nearest through street. Several reasons this works better than cul-de-sacs:
*Cars can still go left or right so it’s not (usually) a dead end
*bikes and pedestrians can still go through just fine
*takes up less space and doesn’t require the road to be rebuilt”
—
And there you have it, folks. Build a grid pattern, but make most of the streets on the grid narrow, non-through streets (or as others have noted car-and-bike-only — and woonerfs might be relevant here too) and you get the same benefits as culs-de-sac –walkable streets which children can safely plan on — with none of the downsides.
Um, “which children can safely PLAY on”, of course.
The research assumes that behavior is identical for people living in cul-de-sac and gird system. And therefore modeling traffic would yield a larger use of automobiles. But, I think that this oversimplifies the problem.
I find that the trend of moving to cul-de-sac communities are more inline with other market and social change that are happening. Here are examples:
1. When the majority of small shops and business are disappearing, driving to the large stores are probably similar form a grid or a cul-de-sac home.
2. I find that my trips to grocery store are less frequent and more planned, since I have to drive through 10 stop signs and a zigzag of roads. I also make sure I make my stops when driving back from work. Oh and thanks to Smartphone, I can compile a list of needed things before leaving the office.
3. The increase in internet based shopping and online ordering of pretty much everything means that the delivery trucks does most of the traveling, reducing the need to shopping from store to store. Maybe one truck takes a longer delivery route but is that worse then having ten cars each taking an individual trip.
4. Entertainment and social activities have been shifting in-house. For example, I guess we are more likely to have a meaningful conversation on line (such as now) than in a bar or I physical location that I have to drive/walk to.
5. Cont. Why drive to the theater if you have an HDTV and you can make your own popcorn?
6. Oh and for saying it is “much harder for emergency vehicles to reach these homes if they’re sequestered in the belly of a web of disconnected dead-ends.” How come I manage to reach anyones home with my $90 GPS device with a +/- 5 minute timing accuracy? Weak argument!
7. The whole idea of safety in an isolate roads versus grid system is that these area are less inviting for anyone to commit a crime when they know that they are more likely to be seen in their vehicle on their way in and out. It is less likely to drive or walk around without being noticed.
8. Again, security systems never been more affordable with features such as remote access and auto emergency notifications.
My point of view, is that there are larger key trends in this country that seems to jive with moving to a cul-de-sac community.
This research over simplifies the issue and arrives to a premature conclusion on the impact on traffic patterns. I have moved 6 months ago to a place that looks more like the left picture and my living patterns do not agree with the conclusion of the study.
Great article. Great responce to it. Keep in mind that the post WWII development of SUBURBS is part of our Military Industrial Complex. And if you’ve ever been to a military base you may have noticed that everything is seperated, just like the Burbs. Ever notice in villages and city’s there is residential above retail? Or that the cool office buildings have restaurants and smoke shops on the first floor? Think about suburban office buildings; boring, usually inoperable windows,acres of asphalt parking that is vacant 2/3 of the time and no one goes there UNLESS THEY HAVE TO. And all those cul-de-sacs, great for parking ; great for parking those Suburban Uh-salt Vehicles, but terrible if you have to walk to somewhere.And to make it worse, seldom are pedestrian paths planned(you can’t sell that space, and who will maintain it?) Give me a good old sidewalk, and a front porch any day.
[...] at 04:00 am | Tagged as: Fredericton, landuse Too often the car-haters treat the cul-de-sac as the enemy of good urban design. They aren’t the most efficient for driving, and they do cost a little more to plow in the [...]
[...] How Cul-de-Sacs Are Killing Your Community. [...]
[...] How Cul-de-Sacs Are Killing Your CommunityMay 7, 2010 [...]
First of all you would think someone who was writing such a “passionate” article would do enough research to know the plural of cul-de-sac is culs-de-sac. This alone and in itself makes me discredit this entire article..if you one can even call it an article. I live in a neighborhood that is almost 90 years old and is filled with culs-de-sac and has been for almost 90 years. This is neighborhood in a large city and it works well and doesn’t disrupt the flow of traffic or cause problems for city planning…it actually enhances the neighborhood by making it seem more park like in the places where the culs-de-sac are located. This article is lame.