(A) Intent. The township recognizes the direct correlation between land use decisions and traffic operations. The intent is to permit accurate evaluation of expected impacts of proposed projects to assist in decision-making. This section is further intended to help achieve the following objectives:
(1) Provide a standard set of analytic tolls and format for preparing traffic impact studies;
(2) Allow the community to assess the effects that a proposed project may have on the community by outlining information needed and evaluation procedures to be used;
(3) Help ensure safe and reasonable traffic operating conditions on streets and intersections after development of the proposed use;
(4) Reduce the negative traffic impacts created by individual developments, and which may negatively impact such developments, by helping to ensure the transportation system can accommodate the expected traffic safety and efficiently;
(5) For rezoning, the traffic impact study is intended to evaluate if the rezoning is timely and, if inconsistent with the Master Plan, if the rezoning would be a logical alternative to the Master Plan, from a traffic perspective;
(6) Realize a comprehensive approach to the overall impacts of developments along a corridor or within part of a community rather than a piecemeal approach;
(7) Provide direction to community decision makers, road agencies and developers of expected impacts of a project;
(8) Alert the community, transportation agencies and developers of improvements or modifications needed to the roadway, access or site design; and
(9) Protect the substantial public investment in the existing street system.
(B) Definitions. For the purpose of this section, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
AVERAGE DAY. A Tuesday, Wednesday or Thursday for most uses. The AVERAGE DAY may be a Saturday for uses that have higher peak-hour traffic volumes on a Saturday rather than mid-week.
DEVELOPMENT. A site plan, subdivision tentative preliminary plat, condominium project, mobile home park, redevelopment, reuse or expansion of a use or building.
GAP (CRITICAL GAP). The median time headway (in seconds) between vehicles in a major traffic stream which will permit side-street vehicles at STOP or YIELD controlled approach to cross through or merge with the major traffic stream under prevailing traffic and roadway conditions.
LEVEL OF SERVICE. A qualitative measure describing operational conditions within a traffic stream, generally described in terms of such factors as speed and travel time, delay, freedom to maneuver, traffic interruptions, comfort and convenience and safety.
MASTER PLAN. The Master Plan for Land Use adopted by the Township Planning Commission which illustrates the intended future land use pattern and may also describe road functional classifications and intended improvements to the transportation system (i.e., Comprehensive Plan, Future Land Use Plan, Thoroughfare Plan and the like).
PEAK HOUR. A one-hour period representing the highest hourly volume of traffic flow on the adjacent street system during the morning (a.m. peak hour), during the afternoon or evening (p.m. peak hour); or representing the hour of highest volume of traffic entering or exiting a site (peak hour or generator).
STUDY AREA. The geographic area containing those critical arterial intersections (and connecting roadway segments) which are expected to be affected by the site-traffic generated by a development.
TRAFFIC IMPACT STUDY. The analysis of the potential traffic impacts generated by a proposed project. This type of study and level of analysis will vary dependent upon the type and size of the project - Abbreviated Traffic Impact Assessment, Rezoning Traffic Impact Study and Traffic Impact Statement.
TRIP. A single or one-direction vehicle movement with either the origin or the destination (exiting or entering) inside a study site.
(C) Applicability. A traffic impact study shall be required and shall be submitted by a petitioner for a rezoning, preliminary site plan, concept plan or subdivision plan (tentative preliminary plat) under any of the situations listed below. The type of study required shall be dependent upon the type and scale of the proposed use and existing traffic conditions.
(1) A rezoning traffic impact study for the following rezoning amendment requests:
(a) Any proposed change of zoning from residential to a nonresidential category;
(b) Any proposed change of zoning from single-family residential to multiple-family residential; and
(c) Any other proposed zoning that would likely increase trips generated per day to and from the subject site by 1,000 or more over one or more principal uses permitted in the existing zoning district, as determined by the Planning Commission following a traffic analysis and recommendation by the township’s planning consultant.
(2) Development proposals. Site plans, plats, mobile home park plans and condominium projects.
(a) A traffic impact statement shall be required for any proposed development which would be expected to generate over 100 directional trips during the peak hour of the traffic generator or the peak hour on the adjacent streets, or over 750 trips in an average day. The following table shall be used by the planning consultant as a guideline in making a recommendation to the Planning Commission. The Township Planning Commission shall determine if a traffic impact statement is required.
Examples of Land Use Size Thresholds Based on Trip Generation Characteristics (1)(2) | ||
Land Use | 100 Peak Hour - Peak Direction | 750 Trips Daily |
Examples of Land Use Size Thresholds Based on Trip Generation Characteristics (1)(2) | ||
Land Use | 100 Peak Hour - Peak Direction | 750 Trips Daily |
Apartments | 245 units | 120 units |
Banks w/drive-in (GFA) | 4,400 sq. ft. | 2,800 sq. ft. |
Church(7) | 17,300 sq. ft. | 20,500 sq. ft. |
Condominiums/Townhouses | 295 units | 120 units |
Convenience Store w/gas (GFA)(3)(5) | 1,300 sq. ft. or 5 pumps | 1,000 sq. ft. |
Day Care Centers | 220 students | 160 students |
Fast Food Rest. w/drive-in (GFA) | 5,200 sq. ft. | 1,200 sq. ft. |
General Office | 55,000 sq. ft. | 45,000 sq. ft. |
Hotel/Motel | 250 rooms | 90 rooms |
Light Industrial | 115,000 sq. ft./8 acres | 115,000 sq. ft. or 11.5 acres |
Manufacturing | 250,000 sq. ft. | 195,000 sq. ft. |
Medical/Dental Office | 37,000 sq. ft. | 26,000 sq. ft. |
Mobile Home Park | 305 units | 150 units |
Research and Development | 85,000 sq. ft./4.5 acres | 70,000 sq. ft. or 4 acres |
Shopping Center/Retail (GLA)(3) | 15,500 sq. ft. | 2,700 sq. ft. |
Single-Family | 150 units | 70 units |
(1) Rates/equations used to calculate the above thresholds are the Trip Generator, 5th Edition, 1991, by the Institute of Transportation Engineers. (2) For example, a full traffic impact study should be completed (100 peak hour, peak direction trips generated) if 150 or more single-family units are proposed for a site. (3) GLA = Gross Leaseable Area; GFA = Gross Floor Area. (4) Using AM peak hour equations would produce a lower threshold. However, adjacent roadway volumes are usually higher during the PM peak hour. (5) Uses both “Service Station with Market” and “Convenience Market with Pumps” data. (6) Uses Convenience Market (24-hour) data (ITE 851). (7) Based on Sunday data. For further trip generation characteristics of the above land uses, or of other uses not illustrated above, refer to the latest version of Trip Generation. | ||
(b) An abbreviated traffic impact assessment shall be required for the following projects: sit-down restaurants with more than 150 seats, fast-food restaurants, banks and savings institutions and convenience/party stores; provided, however, that if one or more threshold in the Table in (C)(2)(a) above is met, then a complete traffic impact statement shall be prepared.
(c) A traffic impact statement or assessment, based on the threshold in division (C)(1) above and this division (C)(2), shall be required for new phases or substantial changes to a development where a traffic study is more than two years old and roadway conditions have changed significantly.
(d) Special land uses shall be required to provide a traffic impact statement based on the thresholds in division (C)(1) above and this division (C)(2).
(D) Traffic impact study contents.
(1) Description of the site, surroundings and study area. Illustrations and a narrative should describe the characteristics of the site and adjacent roadway system (functional classification, lanes, speed limits and the like). This description should include surrounding land uses, expected development in the vicinity which could influence future traffic conditions, special site features and a descriptions of any committed roadway improvements. The study should define and justify the study area selected for analysis.
(2) Description of the requested zoning or use.
(a) Traffic study for a rezoning shall include: a description of the potential uses which would be allowed, compared to those allowed under current zoning. If the use is not consistent with the community’s Master Plan, an explanation of the difference should be provided.
(b) Traffic study for a site plan review, mobile home park, condominium project or subdivision tentative preliminary plat or special land uses shall include a description of factors such as the number and types of dwelling units, the gross and useable floor area, the number of employees and shift change factors. Intended phasing or future expansion should also be noted.
(3) Description of existing traffic conditions.
(a) Traffic counts. Existing conditions including existing peak-hour traffic volumes (and daily volumes if applicable) on street(s) adjacent to the site. Existing counts and levels of service for intersections in the vicinity which are expected to be impacted, as identified by the planning consultant at a pre-application conference or discussion, should be provided for projects requiring a traffic impact statement. Traffic count data shall not be over two years old, except the township may permit counts up to three years old to be increased by a factor supported by documentation or a finding that traffic has increased at a rate less than 2% annually in the past three to five years.
(b) Traffic counts shall be taken on a Tuesday, Wednesday or Thursday of non-holiday weeks. Additional counts (e.g., on a Saturday for a proposed commercial development) may also be required in some cases. The individual or firm performing average or higher than average volume conditions (i.e. regarding weather or seasonal variations and in consideration of any construction or special events) for the area under study.
(c) Roadway characteristics shall be described and illustrated, as appropriate. Features to be addressed include lane configuration, geometrics, signal timing, traffic-control devices, posted speed limits, and any sight distance limitations. Except for rezoning traffic studies, existing levels of service shall be calculated for intersections included within the study area.
(d) Existing driveways and potential turning movement conflicts in the vicinity of the site shall be illustrated and described (not required for rezoning traffic study).
(e) The existing and proposed right-of-way shall be identified (not required for rezoning traffic study).
(4) Background traffic growth. For any project requiring a traffic impact statement with a completion date beyond one year at the time of the traffic study, the analysis shall also include a scenario analyzing forecast traffic at date of completion along the adjacent street network using historic annual percentage increases and/or future development in the area which as been approved. This component is not part of an abbreviated traffic impact assessment or rezoning traffic study.
(5) Trip generation.
(a) Forecasted trip generation of the proposed use for the a.m. (if applicable) and p.m. peak hour and average day. The forecasts shall be based on the data and procedures outlined in the most recent edition of Trip Generation published by the Institute of Transportation Engineers (ITE). The applicant may use other commonly accepted sources of data or supplement the standard data with data from at least three similar projects in the state.
(b) For rezoning requests where a traffic study is required, the study should contrast the traffic impacts of typical uses permitted in the requested zoning district with uses permitted in the current zoning district. The determination of typical uses shall be made by the Planning Commission or planning consultant. For traffic impact assessments or statements, the rates for the specific use(s) proposed shall be used.
(c) Any trip reduction for pass-by trips, transit, ridesharing, other modes, internal capture rates and the like shall be based both on ITE findings and documented survey results acceptable to the township. The community may elect to reduce the trip reduction rates used.
(d) For projects intended to be developed in phases, the trip generation by phase shall be described.
(6) Trip distribution (for assessments and statements only; not for rezonings). The projected traffic generated shall be distributed (inbound v. outbound, left turn v. right turn) onto the existing street network to project turning movements at site access points and, for traffic impact statements, at nearby intersections. Projected turning movements shall be illustrated in the report. A description of the application of standard engineering procedures for determining the distribution should also be attached (trip distribution model, market studies, counts at existing driveways and the like).
(7) Impact analysis (for traffic impact statements only). Level of service or “capacity” analysis at the proposed access points using the procedures outlined in the most recent edition of the Highway Capacity Manual published by the Transportation Research Board. Before and after capacity analysis shall also be performed at the closest signalized intersection for all street intersections where the expected traffic generated at the site will comprise at least 5% of the existing intersection capacity, and/or for roadway sections and intersections experiencing congestion, as determined by the township.
(8) Access design/access management standards. (Not required for a rezoning traffic study). The report shall include a map and description of the location and design of proposed access (driveway or new street intersections) including: any sight distance limitations, dimensions from adjacent driveways and intersections within 200 feet on either side of the main roadway, data to demonstrate the number of driveways proposed in the fewest necessary, support that the access points will provide safe and efficient traffic operation and be in accordance with the standards of the township and the applicable road agency.
(9) Other study items. The traffic impact study (assessment or statement) shall include:
(a) Need for, or provision of, any additional right-of-way where planned or desired by the township or applicable road agency;
(b) Changes which should be considered to the plat or site plan layout;
(c) Description of any needed non-motorized facilities;
(d) If the use involves a drive-through facility, the adequacy of the (queuing or stacking) area should be evaluated;
(e) If a median crossover is desired, separate analysis should be provided;
(f) If a traffic signal is being requested, the relationship of anticipated traffic to traffic signal warrants in the Michigan Manual of Uniform Traffic Control Devices. Analysis should also be provided on the impacts to traffic progression along the roadway through coordination timing and the like; and
(g) Description of site circulation and available sight distances at site driveways.
(10) Mitigation/alternatives. The study shall outline mitigation measures and demonstrate any changes to the level of service achieved by these measures. Any alternatives or suggested phasing of improvements should be described. The mitigation measures may include items such as roadway widening, need for bypass lanes or deceleration tapers/lanes, changes to signalization, use of access management techniques or a reduction in the proposed intensity of use. Proposed mitigation measures shall be discussed with the applicable road agency. The responsibility and timing of roadway improvements shall be described.
(11) Qualifications.
(a) Preparer. The preparation of a thorough traffic impact study requires extensive background and experience in traffic-related analysis. Therefore, the experience of the preparer best defines his or her ability to provide a technically sound analysis. Preparer requirements are outlined below.
1. The person responsible for the preparation of the study shall meet the following requirements:
a. Three or more years of recent experience in the preparation of traffic impact studies;
b. The development of impact studies (and similar intersections and/or corridor analysis) comprise a major component of the preparer’s recent professional experience. This requires ongoing experience and familiarity with the Highway Capacity Manual techniques as well as the computer software (Highway Capacity software and others) that provide level of service results and other analysis findings needed to fully assess potential impacts;
c. Specific education, training and/or professional coursework in traffic impact analysis from an accredited college or university or other professional transportation training organization (such as National Highway Institute, Northwestern University Traffic Institute and the like); and
d. The study preparer shall be an associate (or higher) member of one or more professional transportation-related organizations, such as, the Institute of Transportation Engineers (ITE) or the Transportation Research Board (TRB). This helps ensure that the preparer is maintaining their knowledge as new research is published and analysis techniques are changed or refined.
2. In addition, the preparer should have one of the following professional qualifications:
a. A registered engineer (PE);
b. A community planner with AICP or PCP certification; or
c. A trained professional transportation planner.
3. Any study involving roadway or traffic signal design work shall be prepared by or under the supervision of a registered engineer (PE) with specific training in traffic engineering.
4. The study should include a resume of the preparer responsible for the report. The study may also include relevant experience of the preparer’s firm. The study should also be signed by the preparer with full recognition of potential liability for the results and recommendations outlined in the report.
(b) Reviewer. Review of the study is important to ensure that the analysis and recommendations are based on accepted practices. The traffic impact study shall be reviewed by a trained traffic engineer or transportation planner. The qualifications of the reviewer should parallel those of the preparer’s as outlined above.
(E) Procedures.
(1) The applicant shall discuss or meet with the Township Planner to determine if a study is needed, what type of study is needed and specific items to be addressed.
(2) The applicant submits traffic impact study to the community, with the request for rezoning or preliminary development proposal. A revised study may be required as the scope and details of the request change.
(3) The township distributes the traffic impact study to the appropriate reviewers. A copy may also be submitted to the metropolitan planning organization, transit agency and the like as appropriate for projects or regional significance or along critical corridors.
(4) Reviewers provide community with comments prior to any action on the project.
(F) Waiver of study requirements. The requirement for a traffic impact study, or the study elements listed in division (D) above “Traffic Impact Study Contents” may be waived/modified by the Planning Commission, after a traffic analysis and recommendation by the township’s planning consultant. Reasons for the waiver or modifications shall be documented. Factors to be considered include:
(1) The existing level of service along the roadway is not expected to drop below LOS “C” due to the proposed project;
(2) The existing level of service is not expected to be significantly impacted by the proposed project due to specific conditions at this location; and
(3) A similar traffic study was previously prepared for the site and is still considered applicable.
(Ord. passed 10-11-2000) Penalty, see § 153.999