Idea: Cul-De-Grid, Another Alternative to Grids & Cul-De-Sacs

In my previous 2 posts [The Great Cul-De-Sac Problem] and [The Liquid Grid Street Layout] we discovered that people LOVE living in a cul-de-sac (dead end street). There’s no traffic on your street except locals, it’s just you and your neighbors, it feels safer, more hidden, more maze-like for strangers, and gives off a “cute little village where everyone knows each other” vibe that us white people of European ancestry subconsciously crave. We also discovered the downside. Cul-De-Sacs use up massive amounts of land, promote car use over walking and biking, create traffic bottlenecks, and while they do reward some neighbors with less traffic, they severely punish all other neighbors with heavier traffic and pollution.

Below is an example of an extreme cul-de-sac surrounded by typical cul-de-sacs with inefficient land usage and traffic planning. Terrible walkability, longer commutes, more bottlenecks, etc…

But there’s a reason for people liking their cul-de-sacs and I can’t blame ’em. Most people would rather live on a dead end private street than live right off a main road. So let’s just give the people what they want, with a few compromises.

Keep in mind; my mockups aren’t going to be perfectly accurate.

Here’s a traditional grid of houses:

They’re suppose to somewhat resemble the street layout used here in St. Louis only with everyone having a suburban sized backyard and without the back alleys.


View Larger Map

The grid street layout didn’t stop St. Louis’ devastating suburban sprawl for several reasons (which I’ve mentioned in those past 2 articles and will be discussing even more thoroughly in a future article) but most importantly because:

People. Like. Getting. Away. From. Other. People.

To live in the Suburbs means to live in a secret maze, far away from the city, away from massive amounts of people, on your own street, and to feel hidden. Human beings take comfort in getting away from it all because it translates to safety. More people more problems. With open ended streets like the ones used in Grid Layouts, it feels like everyone in the city has access to your home. Anyone could come by. But with a cul-de-sac it feels more intimate, yes you’re cornered, but it feels like the number of people that can see you or access you is substantially less. The only people that should enter your street are the neighbors you know and trust, and if a stranger’s car drove in you’d know immediately.

So I’d say the main attraction to Cul-De-Sacs are the intimate, dead end, quiet streets. Which I’ve replicated using a grid layout.

Notice how every blue private street has only 8 homes. Residents can walk or bike over a sidewalk connecting blue private streets, without allowing cars and through traffic. So your kids can play hockey and basketball in the street without worry because passerbys will only use the red city streets. There are several advantages to this for the city, and a few compromises for the home owners.

First the bad news:

  • It uses 5% more land than a traditional grid for the same amount of houses.
    • But uses no where near as much land as a cul-de-sac suburban layout.
  • It uses 25% more pavement than a traditional grid layout.
    • But fits a lot more people in less space with less driving than a cul-de-sac layout.
  • Home owners have a 99% increase in the pavement that they must maintain with their tax dollars assuming the dead end streets are turned into private streets that the city is no longer burdened with.
    • But the city’s burden for paving streets is less.

Now the good news:

  • The city’s burden of paving and maintaining streets will be 20% less. Instead those dead end streets can now be considered private streets/driveways and paid for by the locals who live on them. Which makes for a more fair taxation because the city isn’t paying for someone else’s lifestyle choice.
  • The residents are sure to love the more intimate feel and don’t have to move far away from the city in order to get it.
  • More residents can live and work in a smaller space compared to the cul-de-sac suburban layout.
  • Intimacy is created without wasting land the way cul-de-sacs do, yet the simple grid layout keeps traffic flowing by offering numerous ways around congestion or construction.
  • Neighborhoods are much more walkable compared to cul-de-sacs and encourage walking over driving as sidewalks will connect disconnected blue private streets.

So what do you think? I’d LOVE to live in a cul-de-grid, and like the idea a lot better than the Liquid Grid Layout I posted a while back [http://www.chrisnorstrom.com/2011/10/invention-the-liquid-grid-street-layout-a-replacement-for-cul-de-sacs-block-grids/]. Which a commenter has told me has long existed already.

If you find a real world example of a cul-de-grid please let me know in the comments.

7 Comments

  1. King Eric says:

    Ingenious solution, the cul-de-grid is truly the future

  2. Zach says:

    It’s called a pipestem—http://www.waze.com/forum/viewtopic.php?f=8&t=8970

  3. Stephen Ó Bróithe says:

    Who would be responsible for servicing the “private driveways” in blue if there are road problems? Would the residents of that street be responsible?

    Moreover, this likely wouldn’t be possible in jurisdictions with snowfall because the City would need to plow the “private” driveways or the group of families living there would need to be well organized (which is a little idealistic, unfortunately).

    • No it’s just paid for by their taxes. We have a street that was turned into a private street by those living on it. They had it closed off at the end. They still get it maintained they just have to pay for it.

  4. moxiwize says:

    Ok infuriatingly I already typed this and when I tried to post it disappeared, so trying again.

    I was wondering, after having read this and your other stuff on the same subject, what your opinion was of having alleyways, pedestrian access or bikepaths, either behind the backyards or between the houses. Also about having shared public space, like parks and playgrounds linking cul-de-sacs. I have lived in a few places (mostly in Australia) where there have been such accessways, often leading to schools or local shops. My thoughts are that they could foster a positive neighbourhood and community feeling that many people seek, as well as decreasing the desire and reliance on car use (with all the associated negatives of such).

    • Oh I fully support them. They encourage walking over driving. When the straighter line from point a to b is a walkway over a street, it’ll encourage people to walk.

  5. FaceFirst says:

    Some great work here but you are missing a layer of information about the routes you are creating; namely that ‘good’ routes have build fronts addressing them. Your model is similar to the hierarchy of streets you see in the UK, where main routes are pretty dull for pedestrians. You need to have active frontage. And no, lacing a network of pedestrian routes through an otherwise disconnected layout doesn’t encourage people to walk, as the quality and safety of these routes is poor due to the lack of active frontage.

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