TRAFFIC ACCESS AND IMPACT STUDY GUIDELINES & PROCEDURES

These traffic access and impact study requirements define whenproposed comprehensive plan amendment, zone change, subdivisionplans and development plans warrant a detailed traffic access and impactstudy and the type of information that should be included in such a study.All applicants will be required to follow Planning Commissionrequirements and will be treated equally under the same or similarcircumstances.

i. Purpose

The purpose of performing a traffic access and impact study, asdefined by the Institute of Transportation Engineers (ITE), is to:

1. Provide guidance for short- and long-range planning of siteaccess;

2. Provide guidance for on-site circulation and the interfacebetween on-site circulation and off-site traffic;

3. Provide guidance for off-site improvements needed to permitthe roadway system to function satisfactorily so as toaccommodate site and non-site traffic;

4. Assist developers and land owners in making land use siteplanning decisions regarding traffic;

5. Identify the contribution a particular development makes toroadway system traffic volumes;

6. Provide a basis for estimating roadway improvementrequirements attributable to a particular project;

7. Assess the compatibility with local transportation plans(Transportation Element of the Comprehensive Plan);

8. Enable staff to better evaluate zoning changes anddevelopment plans; and

9. Allow appointed and elected officials to know implications oftheir voting decisions.

ii. Qualifications

The traffic access and impact study shall be prepared by or underthe direct supervision of a Technically qualified transportationengineer with training and experience in conducting Traffic accessand impact studies. The professional in charge shall be an activelylicensed Professional Engineer in Kentucky. The Engineer’s seal and

signature shall be placed on the cover page. The submitted reportalso shall include in an appendix the qualifications of the responsibleprofessional plus those of any other transportation professionalstaking part in the study.

iii. When a Study is Required

A traffic access and impact study shall be required when the totalestimated average peak hour trip ends equals 100 or more. Wherelocally-derived trip generation data do not exist, the current editionof the Institute of Transportation Engineers Trip Generation [1] maybe used to estimate the number of peak hour trip ends for aproposed development. “Peak hour” is defined as the peak sixty-minute period that occurs during a typical weekday morning, mid-day or afternoon/evening or on a Saturday.

iv. Pre-Application Meeting

Prior to initiation of the traffic study, a pre-application meeting shallbe held between the Applicant and Georgetown-Scott CountyPlanning Commission (GSCPC) staff. Other invited parties mayinclude the Kentucky Department of Highways (District 7 and/orCentral Office), City of Georgetown and/or Scott County Fiscal Court.Topics to be discussed could include:

Definition of the proposed projectStudy area/transportation facilities to be included in theanalysesHorizon year(s)/analysis scenarios

Opening dateAnticipated buildout or full developmentInterim years or phases

External factors that could affect the proposed developmentPlanned roadway improvementsOther developments nearby

Analysis periodsWeekday A.M. peakWeekday Mid-day peakWeekday P.M. peakSaturday peakOther peak period(s) as necessary (e.g., Toyota MotorManufacturing of Kentucky shift change, special events,etc.)

Traffic dataData to be collectedAvailable data from other sources

Trip generationSource(s)Pass-by and diverted traffic rate assumptions

Methodology for background (non-project) estimates andforecasts

Current traffic volumesForecasts

Methodology for site traffic assignmentsDirectional distribution for approach and departure trafficSite traffic distribution

Analytical toolsHighway Capacity Manual/Highway Capacity SoftwareOther deterministic modelsSimulation

Required performance measuresAdditional analyses needed

Signal warrant analysesSafety studies

Documentationv. Analysis Periods

Operational analyses shall be conducted for peak sixty-minuteperiods:

For a typical weekday A.M. peakFor a typical weekday mid-day peakFor a typical weekday P.M. peak

The GSCPC staff may require an additional analyses for a typicalSaturday peak hour depending on the type of development (retail,for example) and location. Additionally, the GSCPC staff may waivethe need for an analysis of the mid-day peak based on the type ofdevelopment being proposed and location.

vi. Analysis Scenarios

Analyses shall be performed for the required peak periods for thefollowing scenarios:

Existing or base year

Opening year of the proposed project, without the estimatedsite traffic (“No Build”)Opening year of the proposed project, including the estimatedsite trafficBuildout or completion year of the project if the project will beconstructed in multiple phases; completion year, shall beanalyzed with and without mitigation measures (see sectionXIII)

vii. Study Area

Each traffic access and impact study is different, both in the type ofdevelopment being proposed and in its location within Scott County.Thus, the study area and transportation network to be analyzed willbe determined jointly by the applicant and GSCPC staff and willinclude all major arterials and minor collectors that provide access tothe proposed development site. It also may determine that specificminor arterial and collector streets should be included in theanalyses as well. The study area network is to include all proposedaccess points to the project within the adjacent roadway networkand major intersections, both signalized and unsignalized.

viii. Trip Generation

Estimation of site-generated traffic volumes or trip ends should beperformed using a source or sources approved by the GSCPC. Tripgeneration volumes are most commonly computed from datacontained in the latest edition of the ITE Trip Generation manual. Inthe event that data for the proposed land use are not available inTrip Generation or are not appropriate for the proposed land use,data from similar developments should be collected and tripgeneration rates from these data be developed accordingly.Guidelines for collecting trip generation data and developing tripgeneration rates are presented in the ITE Trip Generation Handbook[2]. Traffic generation estimates from data presented in the TripGeneration manual can be made using one of three sources for eachcombination of land use type, independent variable (i.e.development size) and time period:

Data plotWeighted average trip generation rateRegression equation

Guidance for proper use of these sources is presented in the Trip

Generation Handbook and should be followed in performing trafficaccess and impact studies.

Traffic estimates using weighted average trip generation rates orregression equations from Trip Generation represent an averagenumber of trips for a given land use type and independent variable(square feet, for example). After these trip estimates are made, theyshould be increased by ten (10) percent in order to represent atypical “busy” day for the proposed development.

Multi-use developments afford the opportunity for interactionamong land uses within an individual site and thus a reduction intotal trips to and from the site. An internal capture rate can beapplied as a percent reduction to trip generation estimates toaccount for trips internal to the site. Trip reduction for internal tripsis separate from a reduction for pass-by trips. If applicable, internalcapture trips should be subtracted before pass-by trip reductionsare applied. Guidance on the estimation of internal capture rate iscontained in the Trip Generation Handbook.

ix. Trip Distribution and Assignment

Directional distribution of approach and departure site traffic maybe performed in one of the following ways:

In proportion to existing or projected traffic volumes onadjacent streets and roadsUsing the Scott County Travel Demand Model (with assistancefrom the GSCPC)Applying a manual gravity modelBy other means (justification must be provided)Guidance for assignment of project traffic to site access pointsis provided in Transportation and Land Development [3].

x. Allowable analytical tools can be grouped into two generalcategories: macroscopic and microscopic. Any macroscopic tool usedmust implement the most recent version of the Highway CapacityManual [4] (HCM). Several software packages attempt to faithfullyreplicate methods in the HCM and are acceptable for use in trafficaccess and impact studies. However, non-HCM methods such as theIntersection Capacity Utilization (ICU) and percentile delay-basedlevel of service (LOS) shall not be used if contained in a softwarepackage.

HCM methods have limitations and in some cases, microscopicsimulation models will be more appropriate. Situations where HCMmethods are limited and therefore simulation would be moreappropriate include high degrees of oversaturation (i.e., wheredemand exceeds capacity), turn lane overflow, demand starvation(congestion and/or back-ups prohibit turning vehicles from reachingturn lanes), and closely spaced traffic signals on an urban street.

In the event that a proposed roundabout is being evaluated, eitherthe HCM method, microsimulation, or software specifically writtenfor roundabout analyses, may be used.

xi. Performance Measures

Performance measures, qualitative and quantitative, relayinformation on the performance of the transportation system.Performance measures should be appropriate for those facility typesbeing analyzed. The following performance measures, by facilitytype, should be included in traffic access and impact studies:

Unsignalized Intersections

Control delayLOS (HCM only)Volume-to-capacity ratio (v/c) (HCM only)95th-percentile queue

These measures shall be reported for those lanes/lane groupsrequired to yield to through movements (i.e. minor streetapproaches, left turns on major street approaches). A weightedaverage delay for the entire intersection, if computed usingsimulation software, shall not be reported for unsignalizedintersections.

Signalized Intersections

Control delayLOS (HCM only)Volume-to-capacity ratio (v/c) (HCM only)95th-percentile queue

These measures shall be reported for individual lane groups andapproaches.

Urban Streets

Average travel speedNumber of stops (simulation only)Level of service (by segment and overall) (HCM only)

Roundabouts

Control delayLevel of service (HCM only)Volume-to-capacity ratio (v/c) (HCM only)95th-percentile queue

These measures shall be reported for individual lane groups andapproaches.

Two-Lane Highways

Volume-to-capacity ratio (v/c) (HCM only)Level of service (HCM only)

Multi-lane Highways

Average speedDensityLevel of service (HCM only)

xii. Other Analyses

In addition to operational analyses, other analyses of thetransportation system and impacts by the proposed developmentmay be required. These include:

A supporting signal warrant analysis shall be performed if a newtraffic signal is being assumed and/or recommended as part of theproposed development. The warrant analysis shall be performed inaccordance with guidelines presented in the Manual on UniformTraffic Control Devices [5] (MUTCD). Off-peak traffic volumes can beestimated or projected for the purpose of comparison with warrantcriteria. Justification for off-peak traffic estimates must be provided.

Safety Analysis

When determined necessary by the GSCPC staff, a safety analysisshall be conducted for those streets and roads where site access is

being proposed. The analysis shall include an assessment of existingroadway conditions for the following elements: horizontal andvertical geometry, sight distance, pavement condition, shoulderwidth/clear zone width, traffic control, and pedestrian/bicyclefacilities. Crash data (if available) for the last three (3) to five (5) yearsshould be examined. Crash frequencies and rates should betabulated and compared to statewide averages using the mostcurrent version of Analysis of Crash Data in Kentucky [6]. Crashtypes/causative factors should be tabulated and, where determinednecessary by the GSCPC staff, collision diagrams shall be prepared.For those locations where speed is determined to be a significantcausative factor, analyses and recommendations shall include speedmitigation measures.

The crash analysis shall include a discussion of recommendedroadway enhancements to improve safety in the vicinity of theproposed access to the project site and their anticipatedeffectiveness.

Assessment of Transit/Bicycle/Pedestrian Facilities

When deemed desirable by the GSCPC staff, an assessment ofexisting transit, bicycle and pedestrian facilities within the projectimpact area shall be performed by the applicant. The assessmentshall include identification of current transit, bicycle and pedestrianfacilities – description, location, and current condition or state of use.Transit facilities shall include bus stops, especially school bus stops.Pedestrian facilities shall include sidewalks, crosswalks andpedestrian signals at intersections. The assessment also shouldinclude an evaluation of how the proposed development will impactthese current facilities and recommendations for improvements.

xiii. Mitigation

The study should identify current and/or future anticipateddeficiencies in the impact area roadway system, particularly thosedeficiencies that would occur as a result of the proposeddevelopment being built. The study should include feasiblerecommendations to mitigate development impacts and theanticipated effectiveness of those recommendations, bothoperationally and with respect to safety. Cost estimates (to includeengineering, construction and right-of-way) should be provided. Thestudy should also include an assessment of traffic conditions with

construction of the proposed development but without therecommended mitigation improvements.

xiv. Documentation/Supporting Information

The applicant shall submit a final report documenting the studyprocess, the analyses and the results. The report shall be submittedin both hard copy and electronic (PDF) format. The desired numberof hard copies will be determined by the GSCPC staff. The reportshall include the following elements:

Executive summaryDevelopment summaryLocation mapStudy area boundaries and roadway networkStudy area intersection photographs, existing roadway cross-sections, project access points(s), etc.Assessment of existing traffic conditionsTraffic growth and future No Build traffic conditionsSummary of proposed developmentTrip generationTrip distribution, mode split (where applicable), and assignmentAssessment of future traffic conditionsConclusions and recommendationsAppendices

HCS/other software outputSignal warrant analysesPreparer’s qualificationsOther pertinent information

1. Trip Generation, 7th Edition, Institute of Transportation Engineers, Washington, D.C., 2003 (current edition).2. Trip Generation Handbook: An ITE Recommended Practice, Institute of Transportation Engineers, Washington,3. Stover, Vergil G. and Frank J. Koepke, Transportation and Land Development, 2nd Edition, Institute of

Transportation Engineers, Washington, D.C., 2002.4. Highway Capacity Manual, Transportation Research Board, National Academy of Sciences, Washington, D.C.5. Manual on Uniform Traffic Control Devices, United States Department of Transportation, Federal Highway

Administration, Washington, D.C., 2003.6. Analysis of Crash Data in Kentucky, Research Report KTC-07-26/KSP2-07-1F, Kentucky Transportation Center,

College of Engineering, University of Kentucky, Lexington, Kentucky, 2007.