The intent of an impact assessment is to provide relevant information
that is necessary to evaluate the proposal's impact upon the natural
environment, traffic operations, public facility needs and the future
land use of the surrounding area.
An impact assessment includes a written component and a traffic analysis,
as defined in §§ 270-32.3 and 270-32.4. An impact assessment
shall be prepared by the applicant for any of the following projects:
Projects that would be expected to generate 100 directional
vehicle trips (i.e., 100 inbound or 100 outbound trips) during the
peak hour of the traffic generator or the peak hour on the adjacent
streets.
The requirement for an impact assessment may be appealed to the Northville
Planning Commission. The appeal may be to waive the requirement or
eliminate the need for submittal of some of the information. To receive
a modification, the applicant shall demonstrate that the impacts will
be relatively minor and/or the existing infrastructure has ample capacity
available.
Name(s) and address(s) of person(s) that prepared the impact assessment.
Documentation regarding wetlands, woodlands, traffic or fiscal impacts
must be prepared by a person(s) with applicable experience.
A written description of the site's natural features, such as, but
not limited to, topography, soils, wildlife, regulated woodlands,
existing vegetation, wetlands, view sheds, lakes, streams and ponds.
A written description of how the project will comply with the site performance standards contained in Article 3, General Use Provisions, and Chapter 117, Noise.
A description of the proposed uses and other accessory facilities,
to determine compatibility with existing and future land uses, including,
but not limited to, lighting, views from the street and adjacent land
uses, and buffering to minimize impact on adjacent properties.
A description of any hazardous substances expected to be used, stored
or disposed of on the site. The information shall describe the type
of materials, location within the site and method of containment.
Documentation of compliance with federal and state requirements and
a pollution incident prevention plan (PIPP) shall be submitted for
any use that stores more than 25 gallons or 220 pounds of hazardous
materials or wastes. Any discharge of wastewater to a storm sewer,
drain, lake, stream or other surface water shall be documented and
appropriate permits obtained from the Department of Environmental
Quality. A detailed description of any underground storage tanks and
the materials to be stored shall be documented and appropriate permits
obtained from the State Police Fire Marshal Division, Hazardous Materials
Section. If flammable or combustible liquids are to be stored in fixed
aboveground storage containers with a capacity greater than 1,100
gallons, this shall be documented and appropriate permits obtained
from the State Police Fire Marshal Division. Storage of pesticide
or fertilizer in quantities greater than 55 gallons or 100 pounds
shall be documented and appropriate permits obtained from the Michigan
Department of Agriculture, Pesticide and Plant Pest Division. All
necessary permits shall be included within the appendix of the environmental
impact assessment. Best management practices and containment of hazardous
materials shall be documented.
A rezoning traffic assessment shall be required for rezoning requests
that would result in potential uses that are projected to generate
more peak-hour or daily trips than currently zoned uses would generate.
The assessment shall compare the peak-hour and daily trip generation
characteristics between existing and proposed zoning. The trip generation
data shall be based on the most-intense uses permitted in the requested
rezoning district. If the request is for conditional zoning, the trip
generation shall be calculated based on planned use(s). Projected
trip generation shall be based upon equations/rates outlined in the
most-recent version of the Institute of Transportation Engineers (ITE)
Trip Generation Manual.
A traffic impact study shall be required for projects that would
be projected to generate 100 directional vehicle trips (i.e., 100
inbound or 100 outbound trips) during the peak hour of the traffic
generator or the peak hour on the adjacent streets. Forecasted trip
generation shall be based upon equations/rates outlined in the most-recent
version of the Institute of Transportation Engineers (ITE) Trip Generation
Manual. The ITE data may be supplemented by actual trip generation
data from similar establishments in Michigan. Any supplemental data
must be reviewed and approved by the Township prior to use in the
study analyses.
The applicant is required to contact Township staff and the traffic
engineering consultant prior to preparation of a traffic impact study
to discuss available data, extent of study area and inclusion of other
projects or growth factors as part of the background conditions.
Existing conditions, including daily and peak-hour traffic volumes
on adjacent street(s), intersections within the vicinity that are
expected to be impacted, and a description of any sight distance limitations
along the site's frontage, shall be summarized in the study report.
Existing traffic counts shall be taken on a Tuesday, Wednesday or
Thursday of nonholiday weeks. Additional counts, i.e., on a Saturday
for a proposed commercial development, may also be required. The following
times/situations should also be avoided where possible so that the
traffic count data would represent a typical day: construction detours
in the area, summer days for a site near a school, etc. The firm performing
the impact study must make every effort to complete traffic counts
during average or higher than average volume conditions, i.e., regarding
weather or seasonal variations for the area under study. Traffic data
older than two years old will not be accepted. Traffic data between
one and two years old may be accepted when the applicant can document
that volumes have not changed more than 2%.
Projected trip generation of the proposed use shall be provided for
the a.m./p.m. peak-hour and average daily traffic generated. The forecasts
shall be based on the data and procedures outlined in the Institute
for Transportation Engineers (ITE) Trip Generation Manual. The applicant
may use other commonly accepted sources of data or supplement the
standard data with data from similar projects in Michigan. For rezoning
requests when such change represents a departure from the future land
use map, the study should contrast the trip generation 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 Department.
All traffic impact studies will include an analysis of background
conditions for the year that the project is to be completed (or in
phases if applicable). Background traffic includes historic annual
percentage increases and/or acknowledges the traffic impacts of other
uses approved or in the review process, but not yet constructed, which
may affect traffic operations for roadways and intersections near
the subject site, as determined by the Township. This may include
projects in adjacent communities. Improvements identified to address
any poor background conditions must be the minimum required to adequately
address those conditions.
The projected traffic generated shall be distributed onto the existing
street network to identify expected turning movement volumes at site
driveways and nearby intersections and illustrated in the report.
A description of the application of standard engineering procedures
for determining the distribution shall also be included. The expected
trip distribution shall be approved by the Township prior to continuation
of the analyses. The assignment of forecasted site traffic shall be
clearly illustrated in graphic form in the study report.
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 shall be provided.
Before and after capacity analyses shall also be performed at all
street intersections where the expected project traffic will comprise
at least 5% of the existing intersection traffic volumes and/or for
roadway sections and intersections experiencing congestion or a relatively
high accident rate, as determined by the Township or Wayne County
Department of Public Services staff. The "after" analysis shall include
a scenario with no improvements and separate analysis for various
mitigation options or packages of improvements. Any proposed change
to signal timing should include documentation of acceptance by Wayne
County staff.
Traffic crash data at analyzed intersections covering the past three
years shall be summarized in collision diagrams if the segment of
roadway adjacent to or near the subject site has experienced crash
problems.
The location and design of proposed access for a driveway or new
street intersection shall be provided with a map and narrative description.
In addition, analysis shall include any sight distance limitations,
dimensions from adjacent driveways and intersections within 250 feet
and other data to demonstrate that the design and number of proposed
driveways are the fewest necessary. The driveway(s) shall provide
safe and efficient traffic operation and be in accordance with the
standards of this chapter.
The potential need for bypass lanes or deceleration tapers/lanes,
including attachment of any correspondence by the Wayne County Department
of Public Services.
The Township requires analysis using traffic capacity/simulation
software (i.e., SYNCHRO) rather than an isolated intersection capacity
analysis. Such analyses' submittals shall include electronic copies
of the simulation files.