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Thread: Narrower street pavement widths?

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    Cyburbian KSharpe's avatar
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    Narrower street pavement widths?

    Need some help- the boss asked me to do some research regarding skinnier streets for conservation subdivisions. I've seen some sources advocating as small as 18' widths, but none of them address the Engineer's concerns about emergency vehciles, snowplows, etc. Right now we require 28', which is as small as the Engineer is willing to go...any ideas?

  2. #2
    Cyburbian Budgie's avatar
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    Quote Originally posted by KSharpe
    Need some help- the boss asked me to do some research regarding skinnier streets for conservation subdivisions.
    By conservation subdivisions, I assume you mean rural clustering subdivisions (ala Randall Arendt) or are you talking about a TND type of development.
    "And all this terrible change had come about because he had ceased to believe himself and had taken to believing others. " - Leo Tolstoy

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    Cyburbian Jeff's avatar
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    So you want on-street parking?

    In Philly we have 9' streets in some places! Snowplows, firetrucks, any vehicle for that matter w/o a DOT Wide Load Placcard will fit down a 9 footer....

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    Cyburbian Plus PlannerGirl's avatar
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    25 is not at all out of the usual for small streets esp private ones with zero problems from EMS/trash.
    "They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety." Ben Franklin

    Remember this motto to live by: "Life should NOT be a journey to the grave with the intention of arriving safely in an attractive well preserved body, but rather to skid in sideways, chocolate in one hand, martini in the other, body thoroughly used up, totally worn out and screaming 'WOO- HOO what a ride!'"

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    Cyburbian jmello's avatar
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    NCDOT has a set of traditional neighborhood development (TND) guidelines. A "lane" is 18' wide with parking on one side, a "street" is 28' wide with parking on both sides, and a "main street" is 38' with parking on both sides.

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    Cyburbian nerudite's avatar
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    Portland was the original innovator of the 'skinny streets' program, and has a ton of information on it.

  7. #7
    The thought behind 28' is possibly that there is parking on both sides (taking away 16' effectively) leaving a resultant street of 12', or one lane of travel, allowing traffic to duck in and out of parked cars to avoid oncoming cars, thus keeping your speeds down.

    I would suggest several curves and 4-way stops to keep the traffic semi-controlled, raised intersections and speed tables may also help the traffic calming concerns before they -inevitably) happen. Otherwise straight + wide + flat roads = racetrack.
    Who's gonna re-invent the wheel today?

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    Cyburbian Reductionist's avatar
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    Quote Originally posted by KSharpe
    Need some help- the boss asked me to do some research regarding skinnier streets for conservation subdivisions. I've seen some sources advocating as small as 18' widths, but none of them address the Engineer's concerns about emergency vehciles, snowplows, etc. Right now we require 28', which is as small as the Engineer is willing to go...any ideas?
    First and foremost what is the intended design speed for the road? Will there be any bike lanes? yellow road striping? What type of curbing?

    For comparison, arterial roads designed for 45 mph typically have 12 foot lanes, collector road designed for 35 mph have perhaps 11 foot lanes, and local streets designed for 25 mph have 10 foot lanes.

    So in that respect a 28' foot wide roadway with no striping or bike lanes has lane widths probably close to what you'd expect to find on a section of interstate highway with a 70 mph design speed.

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    Cyburbian Budgie's avatar
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    Fort Collins has nice cross sections. LINK
    "And all this terrible change had come about because he had ceased to believe himself and had taken to believing others. " - Leo Tolstoy

  10. #10
    Cyburbian
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    We have allowed two way streets as small as 20' in private developments, with no on-street parking. In developments where we put in the streets, a minimum of 24' and 28' for parking on one side, 32 for both sides.

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    Cyburbian wahday's avatar
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    This website has some information on cities that have adopted narrower street standards. Also, at the end of the page are some good looking resources.

    http://www.sonic.net/abcaia/narrow.htm

    18 feet is pretty narrow, but seems doable (it might be classified as a "yield street" in some places). I had a professor who worked for King County, WA when they were debating a similar issue with the Fire Department who felt the street widths and turning radii hampered their ability to get to a location quick enough. In the end, he created a table comparing pedestrian deaths from wider sreets to fire-related deaths from reduced response times. They finally relented.

    BTW, another strategy I have seen used for emergency vehicle access is rollover curbs that allow them to make tight turns by running up on the sidewalks. Elizabeth MacDonald's Boulevard Book is a good resource for this and other strategies. I saw a talk she gave where she discussed this very issue.
    The purpose of life is a life of purpose

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    Cyburbian KSharpe's avatar
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    Quote Originally posted by Budgie
    By conservation subdivisions, I assume you mean rural clustering subdivisions (ala Randall Arendt) or are you talking about a TND type of development.
    Arendt is the guy....

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    Cyburbian jmello's avatar
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    Quote Originally posted by ssnyderjr
    The thought behind 28' is possibly that there is parking on both sides (taking away 16' effectively) leaving a resultant street of 12', or one lane of travel, allowing traffic to duck in and out of parked cars to avoid oncoming cars, thus keeping your speeds down.
    Extremely underutilized on-street parking in new suburban neighborhoods = drag strip with two 14' lanes.

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    moderator in moderation Suburb Repairman's avatar
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    Quote Originally posted by wahday
    BTW, another strategy I have seen used for emergency vehicle access is rollover curbs that allow them to make tight turns by running up on the sidewalks. Elizabeth MacDonald's Boulevard Book is a good resource for this and other strategies. I saw a talk she gave where she discussed this very issue.
    This is the easiest way to sell the emergency services folks and save yourself some brain damage arguing with them.

    The the one Arendt-style con subdivision that came across my desk at a previous job used side open drainage rather than curb-gutter to lessen impact. With that set-up, emergency vehicle navigation, turning radii, etc. became a non-issue since there were no raised curbs to restrict.

    "Oh, that is all well and good, but, voice or no voice, the people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same way in any country."

    - Herman Göring at the Nuremburg trials (thoughts on democracy)

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    Cyburbian Budgie's avatar
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    Quote Originally posted by KSharpe
    Arendt is the guy....
    Well then, aren't a lot of Arendt's (no pun intended) conservation subdivisions rural. I've always envisions most of these subdivisions with sand/gravel surfaced lanes with narrow width and small ditches. However, don't most of his designs include lanes that are circular in nature and serve in part as one-ways.
    "And all this terrible change had come about because he had ceased to believe himself and had taken to believing others. " - Leo Tolstoy

  16. #16

    Good Resource

    Local Government Commission out of Sacremento is pretty decent as a resource.

    www.lgc.org

    Check it out.
    Forechecking is overrated.

  17. #17
    Cyburbian KSharpe's avatar
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    I like that idea...this is only my first week at this job lol. Thanks for the advice, guys. Are ditches mandatory with side open drainage??


    QUOTE=Suburb Repairman]This is the easiest way to sell the emergency services folks and save yourself some brain damage arguing with them.

    The the one Arendt-style con subdivision that came across my desk at a previous job used side open drainage rather than curb-gutter to lessen impact. With that set-up, emergency vehicle navigation, turning radii, etc. became a non-issue since there were no raised curbs to restrict.[/QUOTE]

  18. #18
    Cyburbian jmello's avatar
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    Quote Originally posted by KSharpe
    I like that idea...this is only my first week at this job lol. Thanks for the advice, guys. Are ditches mandatory with side open drainage??
    Check your county or I-DOT design standards. Also, check with your state water resources authority, if there is one.

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