(A) Traffic Impact Study Defined. A traffic impact study is a complete analysis and assessment of traffic generated by a proposed development, and of the impact on the surrounding transportation system. The study shall be completed and sealed by a licensed professional engineer
(B) When Required. A traffic impact study is required for any proposed development expected to generate over 100 peak hour directional trips. The following table gives examples of land use that is expected to meet or exceed the 100 peak hour directional trip threshold. The City Zoning Administrator will inform the developer of the required impact study.
Examples of Land Use Size Thresholds Based on Trip Generation Characteristics | |
Land Use | 100 Peak Hour Directional |
Examples of Land Use Size Thresholds Based on Trip Generation Characteristics | |
Land Use | 100 Peak Hour Directional |
Residential | |
Single-family | 150 units |
Apartments | 245 units |
Condominiums/Town houses | 295 units |
Mobile Home Park | 305 units |
Shopping Center (GLA) | 15,500 sq. ft. |
Fast Food Restaurant w/drive-in (GFA) | 5,200 sq. ft. |
Gas Stations & Convenience Store w/gas (GFA) | 1,300 sq. ft. or 5 pumps |
Banks w/drive-in (GFA) | 4,400 sq. ft. |
Hotel/Motel | 250 rooms |
General Office | 55,000 sq. ft. |
Medical/Dental Office | 37,000 sq. ft. |
Research & Development | 85,000 sq. ft. |
Light Industrial | 115,000 sq. ft. |
Manufacturing | 250,000 sq. ft |
(C) Review and approval. When required, the traffic impact study shall be reviewed and approved by the Planning Commission prior to approval of the site plan for the development. The Planning Commission shall engage the services of a professional traffic engineer to review the traffic impact study and make comments and recommendations indicating any changes and improvements that will be necessary for the protection of the health, safety, convenience, and welfare of the general public. The applicant shall bear all reasonable expenses incurred by the City in relation to such review.
(D) Contents of study. A traffic impact study should include:
(1) A narrative summary at the beginning of the report, including but not limited to:
(a) The applicant and project name;
(b) A location map;
(c) The size and type of development; and
(d) Generated traffic volumes based on type and size of land use which are compatible with those listed in the Institute of Transportation Engineers publication Trip Generation (current edition).
(2) Project phasing identifying the year of development activities per phase and proposed access plan for each phase.
(3) A transportation system inventory, which describes the physical, functional and operational characteristics of the study area highway system and where appropriate, locate transit services. The description should provide, where pertinent, data on:
(a) Peak-hour volumes (existing and projected);
(b) Number of lanes;
(c) Cross-section;
(d) Intersection traffic signals and configuration;
(e) Traffic signal progression;
(f) Percentage of heavy trucks;
(g) adjacent access point locations;
(h) Jurisdiction; and
(i) Grades.
(4) Plan showing proposed roadway per phase for each access. Driveway design and roadway improvements shall meet Michigan Department of Transportation or St. Clair County Road Commission standards and guides, as applicable.
(5) Capacity analysis shall be performed at each access point. Default values shall not be used when actual values are reasonably available or obtainable. The interaction of conflicting traffic movements shall be addressed in the traffic impact study. Any proposed signalized access within 1/2 mile of an existing signalized intersection shall be analyzed in coordination with the existing signal timing. A time-space diagram should also be included.
(6) A traffic impact study shall be analyzed with and without the proposed development on the existing system, and with the proposed development for both existing and projected traffic volumes.
(a) The traffic volumes for the development shall assume a total build out.
(b) The completed analysis shall be summarized in a table showing all the Measures of Effectiveness (MOE) for all of the above conditions.
(7) Required operational changes shall be part of the site plan approval and driveway permit approval process. All required traffic improvements, determined by the study to be necessary to accommodate or alleviate impacts of the development, shall be fully constructed and completed prior to the issuance of a certificate of occupancy. All cost incurred for the review and construction of the required improvements shall be the sole responsibility of the developer.
(Ord. 04-05, passed 5-20-2004)