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Thread: Best cul-de-sac design

  1. #1
    Cyburbian Streck's avatar
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    Best cul-de-sac design

    Why don't we have a positive feature here in Cyburbia?

    I would like for us to take potential lemons (cul-de-sacs) and see what lemonade has been made from them.

    How about sending in areal photos (or pictures) or design sketches of what Cyburbia members have found to be sucessful cul-de-sac planning and design.

    I think this would be a great forum to promote GOOD solutions to past planning problems. This time it is the cul-de-sac.

  2. #2
    Cyburbian
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    Am looking forward to this thread...!

    In the past twenty years of my career I have seen the cul de sac falling out of favor primarily for safety (exit) reasons - the rationale being that one should be able to get away from a parcel in at least two directions.

    I have seen variations of the cul de sac used specifically to control access in and out of segregated residential areas, and with political change planners had serious problems creating areas that were less vulnerable to being cut off by accidents, repair work, etc.

    My community in Sweden, designed in the 1960s used a lot of cul de sacs, but all of these were joined by paved "sidewalks" that were wide enough for the garbage truck to travel on. Where there were slopes that made getting out when the roads were icy, taking the alternative route over the sidewalk was accepted. But otherwise everybody respects the difference between the road side of the cul de sac and the pedestrian/cycle sidewalk.

    In other countries I've lived and worked, this would definitely NOT function because nobody could resist a shortcut, even if it were not strictly "legal."

  3. #3
    Cyburbian Tide's avatar
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    I think we should start by identifying the types of cul-de-sacs, if there is a 'type' you can associate with each. I think all cul-de-sacs have the same purpose, to maximize land potential by creating false frontages. I think there can be good design but the purpose of a cul-de-sac will not change.

    As for design, do we need 50 foot radii? I am trying to promote green building techniques with bio retention or at the least grass filter areas in the center of cul-de-sacs. Lighting needs, parking needs, accesses, what can we do differently than we have been?

    http://www.hechimovichhomes.com/imag...0Phase%203.jpg
    See the 'cul-de-sac' in the lower left corner, I hate these with a passion. This is where our regulations on lot size, especially frontage can change things to provide for narrower lots with driveways rather than this asphalt half circle.


    SO far have found this interesting link. http://www.uctc.net/access/24/Access...Cul-de-sac.pdf

    Moderator note:
    Leeched image replaced with a URL. Please, use a hotlink friendly site for images. See THIS LINK for rules on Image linking.

    Last edited by NHPlanner; 07 Aug 2007 at 9:38 AM.
    @GigCityPlanner

  4. #4
    Cyburbian mgk920's avatar
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    Man, I interned for the City of FdL in the early 1990s.

    Is this plat south of the railroad on Martin Rd? I was amazed back then how fast the city was growing to the east and southeast and how most of the commercial and industrial was on the city's west side - with the downtown area in between - along with all of those low-level street bridges over creeks and grandfathered 'lowboy' billboards.

    Anyways, most 'dressed up' cul de sacs that I know of just have those little landscaped islands with maybe one or two trees and some flowers in the middle.

    Mike

  5. #5
    Cyburbian boiker's avatar
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    Quote Originally posted by Monamogolo View post
    In the past twenty years of my career I have seen the cul de sac falling out of favor primarily for safety (exit) reasons - the rationale being that one should be able to get away from a parcel in at least two directions.
    In my neck of the woods they have never been more popular. Real Estate developers insist on cul-de-saq'ing as much as possible because they can sell a home for a higher price on a cul-de-saq than they can on a through street.

    The perception of the family-friendly cul-de-saq is alive and well in the heartland of America.

    Furthermore, The elected powers that be would crucify any planner who dare attempted to mess with the laws as they be. They only restriction for cul-de-saqs is a limit on the lenth to 400 feet, which is routinely varied and waived. We don't have limits on the percentage or number of dead-end streets within a sub for the reasons stated above.

    Now, I need to contribute rather than just turning this thread into a b*tch session. I have no good design to offer other than reducing the amount of pavement with a landscaped island in the middle. We have not been fortunate in providing these because our emergency response folks believe these to be detrimental to fighting fires. For one, how do we expect them to manuver their largest ladder truck around that feature? In a neighborhood of two-story homes, we've failed to convince them that they do not need to bring three of their largest pieces of equipment to the scene.
    Dude, I'm cheesing so hard right now.

  6. #6
    Cyburbian Jeff's avatar
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    Quote Originally posted by Tide View post

    As for design, do we need 50 foot radii?
    I think 38' was the smallest radius i could get a passenger car around in AutoTurn.

    However, most municipalities want you to design for a WB-50, or a fire truck, because you know, they are always doing donuts in these things.

  7. #7
    Cyburbian jmello's avatar
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    Quote Originally posted by Tide View post
    See the 'cul-de-sac' in the lower left corner, I hate these with a passion.
    Me too. I am surprised that more people do not find these to be unattractive. The next street over from me has a few of these and the amount of pavement in front of some of the houses is astonishing. If these must be done, a small landscaped island would dress them up immensely.

  8. #8
    Cyburbian Tom R's avatar
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    cul-de-sacs

    Our problem here isn't as much as the design of a cul-de-sac but their length. One community fights for cul-de-sacs consistently. They claim that they create a neighborhood. They have one that is at least a mile long. We argue that such streets create isolation not neighborhoods. We argue the usual safety concerns and the extra travel required for school buses, snow plows etc. but to no avail. As far as the radius is concerned, the "bulb" of the sacs are huge, mainly for snow plows, firetrucks and the like.
    WALSTIB

  9. #9
    Cul-De-Sacs are bad in that they come from sprawl... However IMO, dead end roads need to end in cul-de-sacs to allow people to turn around. But they shouldn't be used for single family housing development or even any housing. The only two good street designs is the American grid, or the Ancient grid-like system.

  10. #10
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    When I was living in Quebec, it wasn't uncommon for cul-de-sacs to have those little round islands in the centre for snow dumps when the streets were cleared in the winter. The snowblowers would fire steady streams of snow onto the centre islands, usually building them up to a dozen feet by January or February.

  11. #11
    Cyburbian JNL's avatar
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    Quote Originally posted by Streck View post
    How about sending in areal photos (or pictures) or design sketches of what Cyburbia members have found to be sucessful cul-de-sac planning and design.
    How would you define "successful"?
    Quote Originally posted by Tom R View post
    Our problem here isn't as much as the design of a cul-de-sac but their length. One community fights for cul-de-sacs consistently. They claim that they create a neighborhood. They have one that is at least a mile long. We argue that such streets create isolation not neighborhoods.
    I'm hearing you. From a crime prevention perspective, the best designs are those that are short and straight. There was some research that looked at burglary risk in cul-de-sacs, and found that houses further in and without sightlines from the adjoining road were at highest risk. I would think that long cul-de-sacs, like the one Tom describes that is over a mile long, defeat the purpose of creating a sense of neighbourhood, and just end up adding to travel time and increasing dependence on vehicle travel.

  12. #12
    Cyburbia Administrator Dan's avatar
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    The comp plans I'm drafting promote interconnectivity, and contain statements like the following;

    The current street standards encourage subdivisions with cul-de-sacs and a looping street pattern. The street network that results may provide difficult or no connectivity between residential areas in the village.

    Greater connectivity promotes mobility and reduces congestion by providing options for people to enter and exit their subdivision. Traffic concentration on a small number of streets, a problem with a hierarchical street network, is less of an issue with a more interconnected street grid. Increasing the number of possible routes to a destination helps public safety services save time reaching a scene of an emergency. Resident survey results show that respondents are very receptive to New Urbanism-style development, a trademark of which is an interconnected street pattern. It also promotes a greater sense of community; residential areas are more integrated into the larger village, rather than isolated as pods.
    ... and policies like:

    TR-1-p5 Require roads in new development to follow principles of traditional neighborhood design, with a grid of streets that provides a high level of connectivity, rather than looping streets, permanent cul-de-sacs, “pods” and other elements that make interconnectivity difficult.
    However, it's to be seen whether such policies will actually be implemented, or whether community officials will ignore the plan and accept the same-old-same-old.

    I've been promoting loop lanes as a cul-de-sac alternative around here, but I'm getting a lukewarm reception from local officials. Traditional cul-de-sacs are seen as "family-friendly", and around these parts, it seems like that's the only demographic that matters. The "think of the children!" mindset here is quite strong.

    Quote Originally posted by JNL View post
    There was some research that looked at burglary risk in cul-de-sacs, and found that houses further in and without sightlines from the adjoining road were at highest risk.
    Do you have a cite? I'd love to reference it in my future plans, even if it's from a study in New Zealand.

  13. #13
    Unfrozen Caveman Planner mendelman's avatar
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    Some design alternatives that seem worthy:

    I like the "eyebrow" design.


    Loop roads are also a good solution.
    Last edited by mendelman; 07 Aug 2007 at 4:40 PM.
    I'm sorry. Is my bias showing?

    The ends can justify the means.

  14. #14
    Cyburbian Streck's avatar
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    JNL asked How would you define sucessful?

    I suppose a sucessful cul-de-sac would be one that has a radius that would allow school buses, moving vans, garbage trucks, and emergency vehicles to turn around without having to back.

    Also, one that can provide enough parking space for occassional visitors when the driveway is full.

    And, one that does not force some house to be "behind" others due to the limitations of street frontage width in curves.

    And one that perhaps has landscaping or some sort of surface treatment to soften the apparent massive amount of paving in a 100 foot diameter circle.

    I think I have just listed what makes cul-de-sacs objectionable - regardless as to whether they are in urban or exurban areas.

    I was just hoping someone had come across some interesting, inovative, and pleasant designs in planning.

  15. #15
    Unfrozen Caveman Planner mendelman's avatar
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    Apart from adding landscaping within the right-of-way, I don't think there is much more that can be done to rethink the "typical" cul-de-sac.

    I really think this discussion should be about design alternatives that embody the "benefits" of a cul-de-sac, but reduce or eliminate its negatives.
    I'm sorry. Is my bias showing?

    The ends can justify the means.

  16. #16
    Cyburbian Streck's avatar
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    Good link by Tide

    Thanks Tide. I just got a chance to read your link. Page three starts a list of advantages of cul-de-sacs including economy of city paving and infrastructure, and the reduction in crime rates.

    The author concludes by recommending consideration of bringing back the cul-de-sac. I agree.

  17. #17
    Unfrozen Caveman Planner mendelman's avatar
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    Quote Originally posted by Streck View post
    The author concludes by recommending consideration of bringing back the cul-de-sac. I agree.
    Bring it back? It hasn't gone anywhere. Still alive and strong in the development world.
    I'm sorry. Is my bias showing?

    The ends can justify the means.

  18. #18
    Cyburbian CJC's avatar
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    Quote Originally posted by Streck View post
    The author concludes by recommending consideration of bringing back the cul-de-sac. I agree.
    Why do you agree? I'm curious.

    To be sure, there are benefits of cul-de-sacs - I grew up on one in Montana and loved the way the city would make huge piles of snow in the middle of ours that we could play on. I can see the desirability from the perspective of a family who is already living a car-dependant lifestyle - it's quiet and remote - for the kids especially. I can see the desirability from the developer's perspective - most of which are noted in that paper. However, from a planning perspective, I can't think of one solid reason to ever advocate for cul-de-sacs.

  19. #19
    Unfrozen Caveman Planner mendelman's avatar
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    Quote Originally posted by CJC View post
    However, from a planning perspective, I can't think of one solid reason to ever advocate for cul-de-sacs.
    Topography constraints is really the best reason for them.
    I'm sorry. Is my bias showing?

    The ends can justify the means.

  20. #20
    Cyburbian CJC's avatar
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    Quote Originally posted by mendelman View post
    Topography constraints is really the best reason for them.
    True, there are some places where they are really the only plausible option.

  21. #21
    mendelman, if you look at the graphic you showed, it says "Sidewalks not required" I think that needs to be a red flag itself.

    Cul-de-sacs are bad in situations where they aren't needed.

    Those are all designs promoting an auto-oriented sprawl oriented design and society.

  22. #22
    Unfrozen Caveman Planner mendelman's avatar
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    Quote Originally posted by HeartlandCityBoy View post
    mendelman, if you look at the graphic you showed, it says "Sidewalks not required" I think that needs to be a red flag itself.

    Cul-de-sacs are bad in situations where they aren't needed.

    Those are all designs promoting an auto-oriented sprawl oriented design and society.
    Yes, I saw that text and really that is immaterial to the discussion here. You need to be less literal and immobile in your position(s). I live in a gridded streetcar suburb where streets have been cul-de-saced to prevent cut through traffic, but pedestrian access is not restricted. Would you despise this place simply because of cul-de-sacs?

    Also, stop your screeding and learn when to respond or not. This thread was created, explicilty, to put forward good designs for cul-de-sacs, not to get people's opinions about cul-de-sacs in general. That has been done elsewhere. Please, if you can't be constructive in a thread, just don't post in it.

    Thank you and good night.
    I'm sorry. Is my bias showing?

    The ends can justify the means.

  23. #23
    I'm just saying the best and only good cul-de-sac designs are ones that aren't in sprawl and don't contribute to isolation, sprawl or automobile oriented societies and design.

  24. #24
    Cyburbian btrage's avatar
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    As mentioned earlier, I think landscaping in the right-of-way could greatly enhance the aesthetics of cul-de-sacs, and probably wouldn't greatly impact emergency service to the homes.

    I really like the "eyebrow" design, displayed earlier. I think some unique designs may be hampered by minimum lot sizes and minimum lot widths. If these could be requirements could be lessened, then I think we would see more intriguing designs.

    Quote Originally posted by HeartlandCityBoy View post
    I'm just saying the best and only good cul-de-sac designs are ones that aren't in sprawl and don't contribute to isolation, sprawl or automobile oriented societies and design.
    I'm starting to get the feeling of a one-trick pony here...

  25. #25
    Nope, I'm just completely anti-Sprawl and pro-Urban/pro-Rural I'm against automobile-oriented societies. Nothing should ever encourage sprawl or automobile orientation in regards to architecture or planning. Cul-De-Sacs are no different. Cul-De-Sacs would be good if designed and used right, but they are not good as they are used now in sprawl.

    This is an example of how to not use Cul-De-Sacs:
    http://maps.live.com/default.aspx?v=...1000&encType=1
    It is Kansas City's worst suburb in the sense that it is the one that has sprawled out more than the city of KCMO itself and prides itself in directly competing and leeching off (with) the main anchor city.

    This is an example of a situation of when Cul-De-Sacs can be used for good:
    http://maps.live.com/default.aspx?v=...1000&encType=1
    Dead end roads in urban or relatively urban/rural areas can be turned into Cul-De-Sacs to allow people to turn around more easily.

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