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Thread: Traffic Studies...When needed

  1. #1
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    Traffic Studies...When needed

    Good Day- I am trying to find information concerning when and at what level a traffic study is required as part of an application for new development. Basically, if there are any triggers that anyone knows of whether its based on square footage or trip generation. We have a fairly built out downtown that has some infill potential.

    Thanks

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    Cyburbian Rumpy Tunanator's avatar
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    Re: Traffic Studies...When needed

    Originally posted by jspence
    Basically, if there are any triggers that anyone knows of whether its based on square footage or trip generation. We have a fairly built out downtown that has some infill potential.

    Thanks
    Depending on the square footage or function of the store, they could both cause increased traffic. A wal-mart would increase traffic huge, while a local Pacos Tacos (copyright, copyright) would not. Most of the chain stores have studies done on existing stores to see what the trip generator would be. Do you have existing counts of PHF(Peak Hour Factors) and HVP (Heavy Vehicle Percentage) for the roads where the infill might occur?
    A guy once told me, "Do not have any attachments, do not have anything in your life you are not willing to walk out on in 30 seconds flat if you spot the heat around the corner."


    Neil McCauley (Robert DeNiro): Heat 1995

  3. #3
    Cyburbian Jeff's avatar
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    Usually when 500 ADT+ is expected to be generated. Some places are more stringent, others less.

  4. #4
    maudit anglais
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    We generally require a traffic impact study for residential developments over 150 units. Commercial is done on a case by case basis. Sometimes we will ask for a traffic impact assessment for smaller developments if there are access or site-specific traffic issues that need to be addressed.

    We also require Traffic Demand Management studies for non-residential developments supplying more than 75 parking spaces.

    A general rule of thumb we sometimes use is is if there are likely to be more than 100 new peak hour trips generated by a proposed land use, we will want a traffic study.

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    Thanks.

    I think we would like to have a graduated requirement. Does anybody have any model ordinances?

  6. #6
    maudit anglais
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    What do you mean by graduated?

    I've never seen TIS requirements put into an ordinance - ours are issued as a separate document "Guidelines for the Preparation of Traffic Impact Studies". It was an instant classic.

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    With a graduated requirement different levels of studies would be required based on anticipated impacts. My community is ultra sensitive to financial burdens on applicants.

  8. #8
    Cyburbian Jeff's avatar
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    I wrote a model ordinance at my old job, I may still have it saved at home, if not its online in alot of S/LD ordinances. I'll check later.

    I don't understand teh "graduated" approach?

    A TIS is either all or nothing. Do you plan on smalle rdevelopments just telling you how many cars are coming, medium telling you how many cars are coming and how bad the roads are going to be, and the biggies will address any necessary improvements??

  9. #9
    Forums Administrator & Gallery Moderator NHPlanner's avatar
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    I'll post our ordinance language tomorrow when I'm back at the office.

    Essentially, we require at least a "short" traffic analysis for every site plan, and a full analysis when certain threshholds are met.
    "Growth is inevitable and desirable, but destruction of community character is not. The question is not whether your part of the world is going to change. The question is how." -- Edward T. McMahon, The Conservation Fund

  10. #10
    Cyburbian Emeritus Chet's avatar
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    Originally posted by jspence
    With a graduated requirement different levels of studies would be required based on anticipated impacts. My community is ultra sensitive to financial burdens on applicants.
    Nope, Here its a full TIA or nothing.

    This it the link to our recently updated Adequate Public Facilities code.

  11. #11
    Forums Administrator & Gallery Moderator NHPlanner's avatar
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    As promised yesterday, from our Site Plan Regulations:

    3.14 TRAFFIC IMPACT ANALYSIS
    a. SUBMITTALS: All projects must provide a report meeting the requirements outlined for a “short” traffic impact analysis. If any of the following conditions apply, then a “full” traffic impact analysis must be completed:
    1. Trip generation exceeding 1,000 average daily trips or 100 peak hour trips. Peak hour is defined as any of the following:
    i. AM peak hour (7-9 AM);
    ii. PM peak hour (4-6 PM);
    iii. Saturday midday peak hour (11AM-1PM); and
    iv. peak hour generator for certain land uses (e.g., school, movie theater) if it falls outside the three previously listed periods. Analysis of Saturday midday peak only applies to retail uses.
    2. The Planning Department may require a “Full” analysis because of special circumstances.

    b. REQUIRED FOR “SHORT” ANALYSES: The “Short” analysis has two primary objectives: First, to justify that a “Full” analysis is not required, and, second, to determine the appropriate impact fee (as outlined in Section XXII of the Zoning Ordinance) imposed on the proponent. At a minimum, the “Short” analysis must include the following:
    1. Description of Site: A brief narrative of the character of the site and adjacent properties, including land uses and other pertinent facts.
    2. Description of Roadways: A brief narrative of the study area roadway facilities, including the number of lanes, speed limit, major intersections, and locations of existing driveways. A description of pedestrian amenities such as sidewalks, crosswalks, and handicap ramps should also be completed.
    3. Sight Distance: Measurements shall be provided for each driveway. A comparison of the available sight distance at each study intersection with Town of Londonderry standards shall be included.
    4. Trip Generation: In all cases, the analysis shall include trip generation based upon the ITE Trip Generation Handbook - latest edition. Where the applicant feels the ITE trip generation is not representative of the proposed development, justification must be provided for alternative trip generation methodology. If counts are performed to determine trip generation rates, the applicant must conduct two separate counts and provide full details of the count locations, including the size of the facility, percent occupancy, location, adjacent road Average Daily Traffic (ADT), time, and date of count.
    5. Trip Distribution: At the “Short” analysis level, trip distribution shall be described in a report that demonstrates knowledge of area-wide land uses, roadway facilities, and predominant traffic flows by time of day. The analysis shall contain a percentage distribution of trips (by direction) to the adjacent roadway facilities and any relevant assumptions. All assumptions made shall be outlined, with justification, in the report.
    6. The report shall be stamped by a professional engineer.

    c. REQUIRED FOR “FULL” ANALYSES
    1. The applicant shall meet with the Planning Department to confirm the study area and study area requirements.
    2. General Requirements: All information described in the “Short” analysis must also be contained in the “Full” analysis.
    3. Existing Traffic Counts: In no case shall existing traffic counts used in the analysis be more than two years old (from date of count to date of analysis submittal). If a significant change (e.g., new roadway or development) has occurred within the last two years, the Planning Department and/or Department of Public Works can, at their discretion, require that new counts be conducted. Traffic counts shall include information on date, time, day of week, and name of the firm or individual who performed the counts. Traffic counts shall be seasonally adjusted to average and peak conditions.
    4. Design Year Traffic Projection:
    i. Design Year: The design year for traffic projections shall be 10 years from the current year.
    ii. The applicant shall obtain a list from the Town of Londonderry containing all proposed developments permitted to date within the study area. The traffic generated by these projects shall be added to the no-build and build analyses. Additionally, the background growth rate should be determined based upon information obtained from the NH Department of Transportation or the Southern New Hampshire Regional Planning Commission. The calculated background growth rate should be completely documented and included in the study for review.
    iii. Trip Generation: Traffic projection for trip generation growth is described in the “Short” analysis section.
    iv. Trip Distribution: The applicant shall provide justification for the assumed trip distribution. The trip distribution methodology should be representative of the type of development. Data may be obtained from employee zip code analysis, studies of similar sites, analysis of ADT on adjacent roadways, US Census journey to work and home-based work/non-work trips, or other sources. Graphic presentation shall be provided showing 1) peak hour trips added by the development, and 2) study area peak hour traffic volumes under each of the following scenarios:
    a. Existing conditions;
    b. Existing conditions with proposed development;
    c. No build for design year, and;
    d. Build for design year .
    5. Peak Hour Capacity Analysis: Capacity analysis is to be performed at all study intersections (including driveways) using the most current Highway Capacity Manual Level of Service methodology for signalized and unsignalized intersections. Each of the four scenarios listed above must be analyzed at a minimum. A gap acceptance analysis should be provided in the case of adjustment to the default critical gap in the capacity analysis.
    6. Safety Analysis: Accident data for the roadways and intersections included in the study area shall be obtained from the Londonderry Police Department. Accident history for the three most recent years available shall be summarized and compared to the Statewide or national rates established for the corresponding facility type (e.g., rural two-lane highway, urban arterial, etc.).
    i. The minimum all season sight distance shall be three-hundred sixty-five (365) feet in all directions meeting the requirements for roadway intersections and Exhibit D3 of the Londonderry Subdivision Regulations.
    7. Trucks: The location of loading docks and/or delivery drop-off areas shall be given in the analysis. The estimated frequency of trucks by time of day shall be provided when the number of daily truck trips exceeds 30 percent of the ADT on any roadway in the study area.
    8. Parking: There should be a defined correlation between estimated trip generation and parking space requirements. The proposal shall contain a comparison of daily and peak hour trip generation estimates to the number of proposed parking spaces on site.
    9. Narrative: Discussion of the following shall be provided:
    i. Travel safety characteristics of any streets substantially impacted by allowing the “build” alternative, considering such things as sight distance limitations, width limitations, horizontal or vertical alignment deficiencies, and surface conditions;
    ii. Streetside safety of any streets substantially impacted, considering such things as the amount and type of development along such streets, presence of sidewalks, vehicle speeds, and any outstanding limitations in sight distance or road configuration;
    iii. Impact on pedestrian safety and convenience;
    iv. Noise impacts on residential premises.
    10. Mitigation: Any mitigating measures proposed shall be described in detail and included in the analysis. It is imperative that the applicants identify improvements to intersections even if they don’t fund them fully. Transportation Demand Management (TDM), non-vehicular transportation and mass transit should be strongly considered as mitigating strategies.

    d. STANDARDS
    1. If not more severely limited under other provisions of other laws or regulations, the absolute increase in calculated intersection delay, under “build” conditions, shall be no more than 10-20 seconds.
    2. Average daily traffic volumes shall not be increased by more than one-third above the “no-build” level on any street.

    e. PROCEDURE
    1. Applicants shall contact the Planning Department early in the project design regarding the scoping of any traffic studies, including consideration of the study area boundary, the definition of “alternative” where involved, and the type of mitigation, if any, which are likely to prove appropriate.
    2. Impact studies shall be submitted at the time of application for site plan review, to allow review prior to the public hearing or meeting at which the project will be presented to the Planning Board.
    "Growth is inevitable and desirable, but destruction of community character is not. The question is not whether your part of the world is going to change. The question is how." -- Edward T. McMahon, The Conservation Fund

  12. #12
    Cyburbian Emeritus Chet's avatar
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    NH - It seems every time I turn around we are using one of your works as a model.

    Kudos.

  13. #13
    Cyburbian Jeff's avatar
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    Is that "short" analysis really necessary? IMO it just seems like waste of time.

    I mean, you know if a "full" analysis is going to be needed based on the number of units or s.f. of the proposed building, right?

  14. #14
    Forums Administrator & Gallery Moderator NHPlanner's avatar
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    Originally posted by Mike D.
    Is that "short" analysis really necessary? IMO it just seems like waste of time.

    I mean, you know if a "full" analysis is going to be needed based on the number of units or s.f. of the proposed building, right?
    Traffic is the #1 issue of my planning board. They required a traffic study for a parking lot expansion, so, yes, in my community, a traffic study is a must for everything.

    Plus, we need at least the short analysis to determine the appropriate impact fee.
    "Growth is inevitable and desirable, but destruction of community character is not. The question is not whether your part of the world is going to change. The question is how." -- Edward T. McMahon, The Conservation Fund

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    Cyburbian donk's avatar
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    We have no set standards, we just "know" when one has to happen.
    Too lazy to beat myself up for being to lazy to beat myself up for being too lazy to... well you get the point....

  16. #16
    Cyburbian Seabishop's avatar
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    Originally posted by NHPlanner
    Traffic is the #1 issue of my planning board. They required a traffic study for a parking lot expansion, so, yes, in my community, a traffic study is a must for everything.

    Plus, we need at least the short analysis to determine the appropriate impact fee.
    Is there anything that doesn' t even need the short study? Little lot splits, tiny commercial developments, etc.?


    Donk said,
    We have no set standards, we just "know" when one has to happen.
    That's how we are, the regs allow the board to request additional studies where warranted.

  17. #17
    Forums Administrator & Gallery Moderator NHPlanner's avatar
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    Originally posted by Seabishop
    Is there anything that doesn' t even need the short study? Little lot splits, tiny commercial developments, etc.?
    We have discretion as staff on when to require one for a subdivision....but on site plans, everything submits a traffic study (the only things we've granted a waiver for are equipment buildings for Verizon, pump stations for water/sewer, and cell towers where the only traffic generated is maintenance related).
    "Growth is inevitable and desirable, but destruction of community character is not. The question is not whether your part of the world is going to change. The question is how." -- Edward T. McMahon, The Conservation Fund

  18. #18
    Cyburbian Jeff's avatar
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    But aren't you just creating more work for yourself? I mean thats one more thing you have to look over. Anything pulling in 100 ADT or less is a drop in the bucket as far as road capacity goes.

  19. #19
    Forums Administrator & Gallery Moderator NHPlanner's avatar
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    Originally posted by Mike D.
    But aren't you just creating more work for yourself? I mean thats one more thing you have to look over. Anything pulling in 100 ADT or less is a drop in the bucket as far as road capacity goes.
    Yes and no. It ends up being reviewed by our review consultant. And then into our review memos to the Planning Board. The Board wants the studies, so I wrote the regulation language and it was adopted by the Board in 2000.
    "Growth is inevitable and desirable, but destruction of community character is not. The question is not whether your part of the world is going to change. The question is how." -- Edward T. McMahon, The Conservation Fund

  20. #20
    Cyburbian Jeff's avatar
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    and sometimes our Boards just don't get the big picture and you're forced to create regs like that

  21. #21
    Cyburbian Emeritus Chet's avatar
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    Originally posted by Mike D.
    and sometimes our Boards just don't get the big picture and you're forced to create regs like that
    You just summed up my community.

  22. #22
    Forums Administrator & Gallery Moderator NHPlanner's avatar
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    Originally posted by Mike D.
    and sometimes our Boards just don't get the big picture and you're forced to create regs like that
    BINGO! We have a winner.
    "Growth is inevitable and desirable, but destruction of community character is not. The question is not whether your part of the world is going to change. The question is how." -- Edward T. McMahon, The Conservation Fund

  23. #23
    Cyburbian donk's avatar
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    Originally posted by Mike D.
    and sometimes our Boards just don't get the big picture and you're forced to create regs like that
    That is why when I redrafted ours I put in lots of

    "and any other item deemed necessary by the Development Officer"
    Too lazy to beat myself up for being to lazy to beat myself up for being too lazy to... well you get the point....

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