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1 Policy and Procedure Traffic Impact Analysis Requirements Dawson County Department of Public Works Transportation Impact Analysis (TIA) Requirements 1) A Transportation Impact Analysis (TIA) evaluates the adequacy of the existing transportation system to serve a proposed development and the expected effects of the proposed development on the transportation system. The TIA should provide adequate information for county staff to evaluate the development proposal and, when appropriate, recommend conditions for approval. 2) Dawson County staff may, at its discretion: a) require additional study components in a TIA or waive requirements deemed inappropriate depending on the specific situation. Dawson County staff may waive a TIA that would otherwise be required if the developer agrees to certain conditions of development, b) Submit the TIA to the Georgia Department of Transportation (GDOT) to review and comment to be included in the County review. 3) Dawson County assumes no liability for any costs or time delays (either direct or consequential) associated with Traffic Impact Analysis preparation and review. Dawson County will pass on the consultant fees charged for TIA reviews by county engineering consultants. When Will a Transportation Impact Analysis Be Required? 1) A Transportation Impact Analysis shall be required for: a) Any proposed development that can be reasonably expected to generate more than 600 vehicle total trips during a single day, and/or more than 100 vehicle total trips during a peak hour. b) Any proposed land use change that, in typical build-out scenarios, can be reasonably expected to generate more than 300 vehicle trip ends more than the previous zoning during a single day c) Any proposed land use change or development meeting the Georgia Department of Community Affairs thresholds for Developments of Regional Impact. A Transportation Impact Analysis may be required for: 1) Any proposed development that can be reasonably expected to generate more than 200 total vehicle trips during a single day, or more than 40 vehicle trips during a single hour. 2) Any case in which, based on the judgment of the Public Works Director, the proposed development or land use action would significantly affect the adjacent transportation system. Examples of such cases include but are not limited to, non-single-family development in single-family residential areas, proposals adding traffic to or creating known or anticipated safety or neighborhood traffic concerns, or proposals that would generate a high percentage of truck traffic (more than 5% of site traffic). Calculation of Trip Generation and Distribution ---PAGE BREAK--- 2 Trip generation data provided in the most recent edition of the ITE publication Trip Generation should be used unless more appropriate data is available. Directional trip distribution assumptions should be based on historical data, existing and future travel characteristics, and capacity constraints Determination Of The Area for Which Analysis Is Required 1) The Transportation Impact Analysis shall address at least the following areas: a) All proposed site access points (public and private roads included). b) Any road segment or intersection where the proposed development can be expected to generate more than 360 additional vehicle trips during a single day or more than 60 additional vehicle trips during a single hour (these typical volumes may need to be adjusted for unusual situations, such as heavy truck traffic, safety issues, or capacity limitations. c) Any road segment or intersection where the additional traffic volume created by the proposed development is greater than 10 percent of the current traffic volume (for road segments) or the current entering volume (for intersections. d) For developments expected to generate more than 30 truck trips per day, the TIA study area shall include the route(s) these trucks would take from the site to and from the arterial roadway GA400. e) Any other intersections adjacent to the subject property. f) For developments expected to generate a significant percentage of truck traffic (more than 5 percent of site traffic), consult Public Works staff to determine the study area. g) Any other intersections identified by Public Works staff as having capacity, safety, neighborhood, and geometric concerns. Current and Future Year Projections 1) The TIA must at a minimum, analyze: a) the existing condition current year, b) anticipated “built-out” year of the development (planned completion not less than 20 years). For larger developments of more than 5 years, it may be appropriate to breakdown the analysis by phases, and c) the anticipated “built-out” year with no development. For “built-out” year projections, the TIA shall select an annual growth rate based on reviewing the GDOT TADA historical traffic count station data for roadways near the site and the Georgia Governor’s Office of Planning and Budget most recent growth projections for Dawson County. The report shall identify the source and included in Appendix. Transportation Impact Analysis (TIA) Report Requirements 1) The County recommends a “Pre-plan/Pre-submittal” consultation with staff of Planning and Development and Public Works. The purpose of the consultation is to outline assumptions and resources prior to preparation of a TIA. To be reviewed, the Transportation Impact Analysis (TIA) report shall include at least the following minimum components (incomplete reports will delay the processing of the land use amendment or plan review). To ease the review, spreadsheets or charting shall be used to compare existing and forecast traffic performance projections. ---PAGE BREAK--- 3 a) The TIA report shall be signed and stamped by a Professional Civil or Traffic Engineer registered in the state of Georgia. b) An executive summary discussing the development, the significant findings of the analysis, and the mitigation measures proposed. c) A vicinity roadway network schematic map showing the proposed project's location concerning the area's transportation system and study area. d) A complete description of the proposed development, including a site plan, with the best available information as to the nature and size of each proposed use and the proposed location and traffic control of all proposed access points (including the distance from all proposed access points to adjacent accesses and streets). e) A brief description of the current (and proposed, if applicable) land uses adjacent to the site, including the location, size, zoning, current use, and future use of any land parcels that are not part of the subject application, but may use the subject parcel for all or part of their access. If there is potential for the development of these parcels, include the best available information as to the likely future use of each parcel. f) A description of the TIA study area, including roadway names, locations and functional classifications, intersection lane configuration, traffic control (including signal timing), existing Right-of-Way, transit routes, and stops (if any), pedestrian and bicycle facilities, and planned transportation system improvements. g) Identify and anticipation of future transportation capital improvement projects and pedestrian improvement projects that may affect the study area based on the County’s Comprehensive Plan and other related master plans. h) Existing traffic volumes (measured during design conditions and the peak season within the previous twelve (12) months, unless County staff deems newer counts necessary due to recent development or seasonal variations). Consult County staff to determine what type of count data (turning movement, ADT, or classification) is necessary. i) The transportation system's existing performance, including Levels of Service (LOS) and Volume/Capacity ratios for all intersections as appropriate within the study area. j) Complete trip generation calculations for all aspects of the proposed development, including the number of trips by vehicle type, size, time of day, and entering/exiting percentages. These figures shall include trip generation figures for any other proposed developments on the subject property and any proposed developments that would share access with the subject property. For developments expected to generate significant truck traffic (more than 30 trucks per day), include separate figures for trucks. Document the sources of this trip generation data. If the source is other than ITE's Trip Generation, the preparer must obtain approval to use such data from county staff before using it in the TIA. k) Trip generation figures for any pending and approved study area developments, if available by the County. l) Identification of the critical analysis period(s) and justification of this identification. m) Trip distribution for the proposed development. For developments expected to generate more than 30 truck trips per day, include separate trip distribution figures for trucks. n) Forecast traffic volumes for Projection Years as stated earlier. ---PAGE BREAK--- 4 o) Forecast performance (including LOS and V/C) of the transportation system for Projection Years as stated earlier. As appropriate, include analysis of signal warrants, signal progression, queue and other traffic flow characteristics. For developments expected to generate a significant percentage of truck traffic, demonstrate how the analysis adequately accounts for the presence of these trucks in the traffic flow. p) Safety analysis of the site accesses, including sight distance (both vertical and horizontal) and operational characteristics. q) As appropriate, analyze right and left turn lane warrants, queue acceleration lanes, throat channelization, and other characteristics of the site accesses utilizing the GDOT Driveway and Encroachment Manual. r) Comparison of the location and spacing of the proposed accesses with Dawson County standards, the appropriate land use for developments within specific Character Areas, and Georgia Department of Transportation standards for developments near state highways. s) Evaluation as appropriate of the turning and traveling characteristics of the vehicles that will be using the proposed development and the adequacy of the geometrics of the existing and proposed roadway (public and private) configurations to accommodate these characteristics. t) Analyzing the effect of the proposed development on pedestrian and bicycle transportation in the area and any new pedestrian or bicycle transportation needs arising from the development, as appropriate. u) Listing of all intersections and locations that are projected to not meet Dawson County (or other jurisdiction, as appropriate) intersection performance standards in the TIA study area during the required analysis period (see methodologies for Dawson County intersection performance standards). v) Description and analysis of mitigation measures necessary to bring these intersections and locations compliant with the applicable standards. Include an analysis showing that these measures will bring these locations into compliance and signal, turn lane, or other warrant analyses as appropriate. The TIA shall also specify the timing and phasing of any new traffic signals and the length of any new turn lanes. Any mitigation measures recommended in the TIA shall be physically and economically feasible, and this feasibility may need to be demonstrated in questionable cases. w) Copies of raw traffic count data used in the analysis (this may be presented in an appendix). x) Calculation sheets and computer software output for all LOS calculations in the analysis. For signalized intersections, this must include the signal timing used in the analysis (this may be presented in an Appendix). y) Warrant worksheets for signals, turn lanes, signal phasing, all-way-stops, and other proposed measures as appropriate (this information may be presented in an appendix). Methodologies and Analysis Parameters 1) The County goal is that all signalized and all-way-stop controlled intersections and roundabouts, except for GA Highway 400, will operate at a Level of Service or better with a Volume/Capacity ratio of 0.85 or less. ---PAGE BREAK--- 5 2) For high percentages of truck traffic, unusual types of intersections, or other cases that do not specifically fit the circumstances for which the above analysis tools are intended, or if the engineer believes that another analysis method more accurately models the situation, consult County staff for determination of the appropriate analysis procedure. Analysis performed using methods not accepted by County staff will not be processed for review. 3) Signal timing used in capacity analysis shall use the same cycle length currently used at the intersection unless specifically noted otherwise. Proposed signal timing modifications should be consistent with GDOT and national guidelines. 4) All calculations and analysis results should be reasonable, understandable, consistent, and thoroughly explained. Calculations, graphs, tables, data, and analysis results contrary to common sense will not be accepted and may lead to the TIA being returned to the applicant's representative for correction. 5) The conclusions presented in the TIA shall be consistent with and supported by the report's data, calculations, and analysis. Inconsistent and unsupported findings will not be accepted and will lead to the TIA being returned to the applicant's representative for correction. Transportation (Roads). 1) A Transportation Impact Analysis must include the improvements necessary to correct any identified Road deficiencies and maintain existing service levels for existing and proposed Development. Dawson County shall satisfy the Level of Service review procedure through one of the following actions during the Land Use Amendment or Land Development review process. a) Land Use Amendment or Permit is issued subject to the condition that, at the time of the issuance of a Certificate of Occupancy or its functional equivalent, the necessary facilities and services are in place and available to serve the new Development or: b) At the time the Land Use Amendment or Permit is issued, the necessary facilities and services are guaranteed in an enforceable Development agreement, or an agreement or Land Use Amendment issued to be in place and available to serve new Development at the time of the issuance of a Certificate of Occupancy or its functional equivalent; or c) Necessary improvements that are programmed within the first three years of the Five-Year Schedule of Capital Improvements provided that all of the following conditions are met: i) The Five-Year Capital Improvements Program and the Capital Improvements Element of the Dawson County Comprehensive Plan are funded and feasible. The Level of service determination shall only include Transportation projects scheduled in or before the first three years of the Five-Year Schedule of Capital Improvements. ii) The Five-Year Capital Improvements Program includes improvements necessary to correct any identified Road deficiencies and maintain adopted levels of service for existing and Permitted Development within the first three years of the Five-Year Schedule of Capital Improvements, and the provision of service will commence in or before that third year. iii) The public transportation facilities necessary to serve the Development are available or included in or before the first three years of the Five-Year Schedule of Capital Improvements. Land Use Amendments are only issued on this condition. ---PAGE BREAK--- 6 iv) The Five-Year Capital Improvements Program is based on available revenue sources. It identifies whether funding is for design, engineering, consultant fees, or construction and indicates, by fiscal year, how the dollars will be allocated. ---PAGE BREAK--- 7 Transportation Impact Analysis Report Minimum Requirements: P.E. Stamp and Signature Executive Summary Roadway network schematic Map Development Description and Site Plan Description of Adjacent Parcels and Developments Existing Traffic Volumes Accident Data Existing performance of Transportation Systems Complete Trip Generation Data and Explanation Trip Generation Figures for Development Affecting the Study Area Identification and Justification of Critical Analysis Period Trip Distribution Forecast Traffic Volumes Without Development Forecast Performance of Transportation System Without Development Forecast Traffic Volumes with Development Forecast Performance of Transportation System With Development Safety Analysis of Site Accesses (vertical and horizontal) Analysis of Applicable Warrants at Site Accesses Comparison of Proposed Access Spacings with GDOT Driveway and Encroachment standards Analysis of Other Adverse/Controversial Effects Analysis of Development Effects on Pedestrian and Bicycle Needs Listing of Intersections Projected not to meet Level of Service Standards Recommendations for transportation improvements Mitigation Description and Demonstration of Adequacy and Feasibility Raw Traffic Count Data Calculation Sheets and Software Output Applicable Warrant Worksheets