The TIA shall follow standard transportation engineering processes for determining trip generation and distribution including trip generation category, diversion assumptions, distribution assumptions, the adequacy of the road network to serve the proposed development, and whether off-site road dedication and improvements should be made to mitigate the effects of the development proposed in the application. The data and methods used in the TIA shall be based upon the latest editions of Institute of Transportation Engineers (ITE) manuals. A TIA shall address the factors listed below:
A. Executive Summary. At the beginning of the TIA, the executive summary shall summarize the analysis and conclusions and identify recommended transportation improvements.
B. Site Description. The TIA shall contain reports, graphics, illustrations, narratives, and a site plan that describe the characteristics of the site and adjacent land uses as well as expected development in the vicinity that will influence future traffic conditions. A description of potential uses and traffic generation to be evaluated shall be provided. A description of the proposed development, including access plans, staging plans, and an indication of land use and intensity, shall be provided.
C. Study Area. The study area shall include all proposed access points, all signalized intersections and all non-signalized intersections having side-street average daily traffic counts of 2,000 vehicles per day or more within one-half mile of the property lines on all streets adjoining the site in accordance with Table 6.13.7.C: Study Area Boundaries. If the estimated trip generation for the project is over 2,500 trips per day, then the study area shall include all proposed access points, all signalized intersections, and all non-signalized intersections having side-street average daily traffic counts of 2,000 vehicles per day or more within one mile of the property lines on all adjoining streets. The potential traffic from any approved project shall be considered in the study as determined by the Planning Director. The Planning Director has the right to add or subtract study area intersections based on specific study area characteristics, and local traffic patterns.
Element | <
2,500
Trips Per Day | >
2,500
Trips Per Day |
All proposed access points | Yes | Yes |
All signalized intersections within 1/2 mile | Yes | Yes |
All signalized intersections more than 1/2 mile but within one mile of site | No | Yes |
All non-signalized intersections within 1/2 mile of the site with at least 2,500 average daily trips | Yes | Yes |
All non-signalized intersections more than 1/2 mile but within one mile of the site with at least 2,500 average daily trip | No | Yes |
D. Intersections Shall be Analyzed under Four Scenarios.
1. Existing.
2. No-build: (existing + annual growth + approved developments).
3. Build: (existing + annual growth + approved developments + site traffic).
4. Build improved: (existing + annual growth + approved developments + site traffic + necessary improvements).
5. Scenario 4 may be eliminated if improvements are not necessary to satisfy any queuing problems or the LOS criteria listed herein. Overall LOS and delay must be provided for all signalized intersections and worst movement LOS and delay must be provided for all unsignalized intersections. Intersection analysis shall include queue analysis. The analysis year for all future scenarios is one year following the development's scheduled completion year (build + 1).
E. Existing Traffic Conditions. The TIA shall contain a summary of the data utilized in the study and an analysis of existing traffic conditions, including:
1. Traffic count and turning movement information, including the source of and date when traffic count information was collected;
2. Correction factors that were used to convert collected traffic data into representative design-hour traffic volumes;
3. Roadway characteristics, including the design configuration of existing or proposed roadways, existing traffic control measures (e.g., speed limits and traffic signals), and existing driveways and turning movement conflicts in the vicinity of the site; and
4. Identification of the existing level of service for roadways and intersections without project development traffic using accepted methods of evaluation. Level of service should be calculated for the weekday peak hour and, in the case of uses generating high levels of weekend traffic, the Saturday peak hour.
F. Level of Service. For corridors, including mainline, merging areas, and ramp junctions, a LOS C shall be maintained on any expressway, freeway, or arterial, and an LOS D on any other designated nonlocal street on the thoroughfare plan. At all intersections, an LOS C shall be maintained on any arterial or higher-order street and an LOS D on any other nonresidential street. Where the existing level of service is below these standards, the traffic impact analysis report shall identify those improvements or transportation demand management techniques needed to maintain the existing level of service, and what additional improvements would be needed to raise the level of service to the standards indicated.
G. Number of Access Points. The number of access points provided shall be the minimum needed to provide adequate access capacity for the site. Evidence of LOS D operations for individual public street movements at access locations is a primary indication of the need for additional access points. However, the spacing and geometric design of all access points shall be consistent with the access management criteria of the ordinance.
H. Traffic Flow and Progression. The location of new traffic signals or proposed changes to cycle lengths or timing patterns of existing signals to meet level of service standards shall not interfere with the goal of achieving adequate traffic progression on major public streets in the vicinity of the development.
I. Vehicle Storage. The capacity of storage bays and auxiliary lanes for turning traffic shall be adequate to ensure that turning traffic will not interfere with through traffic flows on any public street.
J. Internal Circulation. On-site vehicle circulation and parking patterns shall be designed so as not to interfere with the flow of traffic on any public street and shall accommodate all anticipated types of site traffic.
K. Safety. Access points shall be designed to provide for adequate sight distance and appropriate facilities to accommodate acceleration and deceleration of site traffic. Where traffic from the proposed development will impact any location with an incidence of high accident frequency (defined as one of the five to ten highest accident locations in the area), the accident history should be evaluated and a determination made that the proposed site access or additional site traffic will not further aggravate the situation.
L. Horizon Year(s) and Background Traffic Growth. The TIA shall identify the horizon year(s) that were analyzed in the study, the background traffic growth factors for each horizon year, and the method and assumptions used to develop the background traffic growth. Background growth rates should be developed using historical traffic counts and/or population and employment growth in the area, with a maximum of 6% per year. Unless otherwise approved by the Planning Director, the impact of development shall be analyzed for the build out year plus one year into the future after the development is completed.
M. Time Periods to be Analyzed. For each defined horizon year, specific time periods are to be analyzed. For most land uses, this time period will be the average peak hour a.m. and p.m. However, certain uses (e.g., major retail centers, schools, or recreational uses) will have characteristic peak hours different than that found for adjacent streets, and these unique peak hours may need to be analyzed to determine factors, such as proper site access and turn lane storage requirements.
N. Trip Generation, Reduction, and Distribution. The TIA shall summarize the projected peak hour and average daily trip generation for the proposed development and illustrate the projected trip distribution of trips to and from the site, and should identify the basis of the trip generation, reduction, and distribution factors used in the study. Trip distribution assumptions should be based on existing traffic patterns and employment and population centers in the area.
O. Traffic Assignment. The TIA shall identify projected design-hour traffic volumes for roadway segments, intersections, or driveways in the study area, with and without the proposed development, for the horizon year(s) of the study.
P. Impact Analysis. The TIA shall address the impact of traffic volumes of the projected horizon year(s) relative to each of the applicable traffic service standards and shall identify the methodology utilized to evaluate the impact. The weekday a.m. and p.m. peak hour impact shall be evaluated as well as the Saturday peak hour for those uses exhibiting high levels of weekend traffic generation.
Q. Mitigation/Alternatives. In situations where the traffic levels of service standards are exceeded, the traffic impact report shall evaluate each of the following alternatives for achieving the traffic service standards by:
1. Identifying where additional rights-of-way are needed to implement mitigation strategies; and
2. Identifying suggested phasing of improvements where needed to maintain compliance with traffic service standards.
R. Recommendations. The TIA shall clearly state the mitigation measures recommended by the analysis and shall summarize how the recommended mitigations are roughly proportional to the identified impacts. The recommended street and highway mitigation measures shall be shown on a drawing that depicts existing and recommended improvements.
S. Other. Other items may be required at the discretion of the Town Manager, Planning Director, or Public Works Director depending upon the type and scale of the project. These may include, but are not limited to: queue length analysis, pedestrian counts, accident data, traffic speeds, stopping sight distances, and signal warrant analyses.
(Ord. 2020-36, passed 12-2-2019; Ord. 2023-38, passed 5-1-2023)