The Township Board finds that, as a predominantly residential
island community, Grosse Ile Township has unique challenges to ensure
that the island remains a sustainable community. The island is vulnerable
to large-scale development having a significantly adverse impact on
transportation and the ability of the community to provide the necessary
infrastructure and services. This chapter is intended to provide for
the comprehensive and systematic analysis of the impact and assessment
of proposed mitigation for any major development through:
A. Providing for Township review and approval of developments that may
have a significant impact on transportation, utilities and community
services.
B. Assisting applicants, the Township and the general public in understanding
the impacts of development and identify possible changes to the development
proposal or improvements to roadways, utilities and infrastructure
to mitigate the impact.
C. Ensuring land use decisions are made with consideration to the findings
and recommendations in the Township's Master Plan.
D. Ensuring adequate utility capacity, including sewer, water, and electricity
to ensure that adequate public facilities and services are available
concurrent with new development so that orderly development, and growth
can occur and protect the public health, safety, and welfare, which
can be damaged by exceeding utility capacity.
E. Ensuring that the build out of the Township does not exceed capacity
of the Township wastewater treatment system.
F. Ensuring safe and reasonable transportation conditions on roads and
intersections and protect the public health, safety, and welfare,
which can be damaged by unmanaged increases in traffic congestion.
G. Ensuring safe and reasonable transportation operating conditions
on streets and intersections after development of the proposed use.
H. Ensuring that the build out of the Township does not exceed the capacity
of the bridges leading to the island.
I. Protecting the substantial public investment in the existing street
and utility system.
J. Ensuring that any changes to land use or zoning will not adversely
impact the fiscal health of the Township and will maintain a fiscally
balanced land use balance.
K. Coordinating the environmental protection measures required under various ordinances, including, but not limited to: Chapter
71, Condominium Projects, Chapter
98, Environmental Assessment, Chapter
238, Subdivision Control, Chapter
275, Wetlands and Drainageways, Chapter
282, Woodland and Tree Preservation, and Chapter
285, Zoning.
The following terms used in this chapter shall be defined as
follows:
APPLICANT
An individual, partnership, corporation (or agent thereof), or other entity that undertakes the responsibility for any or all of the activities covered by this chapter or Chapter
71, Condominium Projects, Chapter
98, Environmental Assessment, Chapter
238, Subdivision Control, or Chapter
285, Zoning.
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.
BACKGROUND TRAFFIC
Traffic anticipated to occur regardless of the decision on
the subject application based on overall trends as demonstrated by
annual traffic increases and associated with specific approved projects
for the opening year of a project. Data such as historic counts and
long-range traffic projections from the SEMCOG model shall be considered
as part of the background traffic calculation.
CAPITAL IMPROVEMENT PLAN (CIP)
An annual document adopted by the Township indicating capital
projects having funding approval for the current fiscal year and those
capital projects which are currently planned for the following five-year
period, including the proposed means of financing the same.
DEVELOPMENT
A site plan, subdivision tentative preliminary plat, condominium
project, mobile home park, redevelopment, reuse or expansion of a
use or building.
GAP (CRITICAL)
The median time headway (in seconds) between vehicles in
a major traffic stream which will permit side-street vehicles at a
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.
A.
LEVEL OF SERVICE AOperations with very low control delay occurring with favorable progression and/or short cycle lengths.
B.
LEVEL OF SERVICE BOperations with low control delay occurring with good progression and/or short cycle lengths.
C.
LEVEL OF SERVICE COperations with average control delays resulting from fair progression and/or longer cycle lengths. Individual cycle failures begin to appear. It is typically determined to be acceptable for signalized intersections and the bridges leading to the island.
D.
LEVEL OF SERVICE DOperations with longer control delays due to a combination of unfavorable progression, long cycle lengths, or high V/C ratios. Many vehicles stop and individual cycle failures are noticeable. It is typically determined to be acceptable for unsignalized intersections.
E.
LEVEL OF SERVICE EOperations with high control delays due to a combination of poor progression, long cycle lengths, and high V/C ratios. Individual cycle failures are a frequent occurrence. This is considered to be the limit of acceptable delay.
F.
LEVEL OF SERVICE FOperation with control delays unacceptable to most drivers occurring due to over saturation where arrival rates exceed the capacity of the intersection, poor progression, or very long cycle lengths.
MASTER PLAN
A document which is adopted under the guidance of the Planning
Commission in accordance with the Michigan Planning Enabling Act (Public
Act 33 of 2008, as amended) and consists of graphic and written materials
which indicate the general location for streets, parks, schools, public
buildings and all physical development of the Township.
PEAK HOUR
A one-hour period representing the highest hourly volume
of traffic flow in 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 of generator).
PLANNING COMMISSION
The Planning Commission of the Township of Grosse Ile, Wayne
County, Michigan.
PUBLIC SAFETY FACILITY
A unit dedicated to providing immediate and direct emergency
response to fire, medical service, crime, and other community safety
needs.
ROADS
A public or private thoroughfare or right-of-way, other than a public or private alley, dedicated to or designed for travel and access to any land, lot or parcel, whether designated as a road, avenue, highway, boulevard, drive, lane, place, court, or any similar designation. Various types of roads are defined in Article
1 of Chapter
285, Zoning.
SEMCOG
The Southeast Michigan Council of Governments; the region's
designated Metropolitan Planning Organization for Southeast Michigan.
STRUCTURAL ADEQUACY
Determination by the Township Engineer or the Wayne County
Department of Public Services, that the pavement cross section (or
bridge design) is of sufficient depth and design to carry the increased
traffic volume generated by the proposed development, including the
heavy construction vehicles which will be present, without causing
undue failure of the infrastructure.
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.
TRIP (i.e., DIRECTIONAL TRIP)
A single- or one-direction vehicle movement with either the
origin or the destination (exiting or entering) inside a study site.
UNDEVELOPED AREA
A land area that is removed by more than 200 feet from existing
utilities and improved roads and has not been previously improved
with roads and utilities. Any previously platted lots that are unimproved
and currently do not have road and utility access shall be considered
an undeveloped area. Any out island that is separated from the main
island of the Township and currently does not have road and utility
access shall be considered an undeveloped area.
The following information is required for transportation impact
studies:
A. Study area. The analysis should define and justify the study area
selected for analysis, subject to approval by the Township.
(1) A transportation impact assessment shall study the site access and
adjacent roadways.
(2) A transportation impact statement shall study the larger area of
the Township that is influenced by traffic from the development. At
a minimum this shall include any signalized intersection between the
site and the closest bridge leading to the island. The study shall
also include impacts to both bridges leading to the island.
(3) For a rezoning, a transportation comparison shall provide a comparison
of the trip generation between existing and proposed zoning and potential
traffic impacts resulting from a rezoning. This study shall document
the transportation impacts of the net increase in traffic.
B. Existing site conditions. Illustrations and a narrative shall be
provided that describes the characteristics of the site and adjacent
roadway system (planned and existing right-of-way, functional classification,
lane configuration, speed limits, any sight distance limitations,
locations and potential conflicts with operations at existing access
points or intersections within 250 feet of the site's frontage,
or greater based upon MDOT access management guidelines, current traffic
conflicts, etc.). This description should include surrounding land
uses, expected development in the vicinity which could influence future
transportation conditions, special site features and a description
of any committed roadway improvements.
C. Existing traffic conditions. Illustrations, narratives, tables and capacity analysis that reflects existing traffic conditions for the study area defined in §
70-4A above shall be provided, including the following.
(1) Roadway alignment, including any problems with sight distance, number
of lanes, lane width and lane configurations.
(2) Roadway pavement conditions.
(3) Posted speed limits for various segments.
(4) Existing traffic control.
(5) Existing signal timing, as applicable.
(6) Existing peak-hour weekday traffic volumes and daily volumes or peak
period counts (7:00 a.m. to 9:00 a.m. and 4:00 p.m. to 6:00 p.m.)
to support the selection of the evaluated peak hour (if applicable)
on street(s) adjacent to the site. For uses with weekend peak characteristics,
the Township may require new counts be taken on typical weekend days
during the anticipated peak hours of the proposed use. All counts
shall be collected using accepted practices and shall not be over
two years old.
(7) Existing counts and levels of service for intersections in the study
area shall be performed. Existing counts and levels of service for
the closest bridge leading to the island shall also be performed.
(8) Crash data shall be provided and analyzed for the most recent three-year
period upon which information is available for sites in close proximity
to intersections identified as either a "critical crash location"
or a "fatality" location. SEMCOG data or UD-10 reports should be used
in the analysis. Critical crash locations should be identified using
SEMCOG's critical crash thresholds. The Planning Commission may
waive this requirement upon a finding that the crash potential would
not be significantly impacted by the proposed project.
D. Nonmotorized conditions. Illustrations, narratives and analysis that
reflect existing nonmotorized transportation conditions shall be provided,
including:
(1) Pedestrian level of service shall consider presence of sidewalks,
adequate sidewalk width based upon number of pedestrians and bicycles,
good lateral separation with buffers from traffic, traffic volume
and speed on adjoining street, crossing opportunities on major streets,
presence of traffic signal controls, number of driveways crossing
sidewalk, block size and connectivity to adjacent development.
(2) Bicycle level of service shall consider presence of multi-modal pathway
or bike lane, pavement condition, adequate width of bicycle travel
lanes, average bicycle travel speeds, average control delay for bicycles
at signalized intersections, network connectivity, traffic volume
and speed on adjoining street, and amount of trucks encountered.
E. Background traffic conditions. Projects that are not expected to
be completed and occupied within one year of site plan approval shall
provide a separate evaluation of background traffic for the expected
completion date of the proposed development. This background traffic
shall be based on historic counts to acknowledge general growth trends
in the area, plus traffic associated with approved developments, either
currently under construction or approved (and would be operational
before the build-out year of this proposed project), in the project
area. The background traffic shall be evaluated based on the existing
road system plus programmed improvements where funding has been committed.
A level of service analysis shall be performed for each intersection
in the study area. Unfunded mitigation that is not programmed by Wayne
County, the Township or included in the SEMCOG five-year TIP shall
not be provided under the background conditions. Background traffic
turning movements shall be illustrated in the report.
F. Proposed use.
(1) For a site plan review, mobile home park, condominium project, a
subdivision plat or special land use: a description of factors that
relate to project trip generation, such as the number and types of
dwelling units, the gross and usable floor area, the number of employees
and shift change factors shall be provided. Intended phasing or future
expansion shall be noted.
(2) For a rezoning, a description of the potential representative uses
which would be allowed, compared to representative uses allowed under
current zoning. Representative uses shall include the most intense
traffic generation use allowed under current zoning in compliance
with all Township site development regulations.
G. Trip generation forecast. Forecasted trip generation of the proposed
use for the a.m. peak hour, the p.m. peak hour and average day shall
be provided for the overall project and each phase. 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. The applicant may use other commonly accepted and published
sources of data or supplement the standard data with data from at
least three similar projects in Michigan.
H. Trip reduction. Any trip reduction for pass-by trips, ride-sharing,
other modes and internal capture rates shall be based both on ITE
findings and documented survey results acceptable to the Township
and Wayne County. Trip reduction factors shall be subject to Township
approval.
I. Trip distribution. 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 nearby
intersections where required. Projected turning movements shall be
illustrated in the report. A description of the application of standard
engineering procedures for determining the distribution should be
provided, such as trip distribution model, market studies or counts
at existing driveways.
J. Access point level of service. A level of service or capacity analysis
is required 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. The capacity analysis should
be provided in the appendix of the report.
K. Intersection level of service. Capacity analyses shall be provided for all street intersections and bridges for the study area defined in §
70-4A under the following conditions:
(1) Existing traffic under existing road conditions.
(2) Future project traffic under existing road conditions with programmed
road improvements that will be completed before the build-out year
of this proposed project.
(3) Future traffic, including project and background, under background
road conditions. Background road conditions shall include the existing
road system plus programmed improvements where funding has been committed.
L. Warrant analysis. A traffic signal warrant analysis based on the
procedures outlined in the Michigan Manual of Uniform Traffic Control
Devices shall be performed for unsignalized intersections identified
with an existing Level of Service D or worse for existing conditions.
The signal warrant analysis should contain, at a minimum, Warrants
1, 2, 6, 9, and 11. For unsignalized intersections projected to operate
at Level of Service D or worse under background or future conditions,
an assessment using the peak hour (Warrant 11) shall be provided.
At least two traffic signal warrants should be met to warrant a signal.
M. Bridge. For a transportation impact statement, capacity analyses
shall also be provided for the bridges leading to the island, including
intersections on both sides of the bridges. The analysis shall take
into consideration delays caused by bridge openings for boat traffic
and the capacity of toll booths. An assessment shall also be made
of the impact of additional population on the capacity of the bridges
to evacuate the island in the event of emergency.
N. Access design. The report shall include a map and description of
the location and design of proposed access (driveways or new street
intersections), including:
(1) Sight distance limitations and sketches from field notes.
(2) Dimensions from adjacent driveways and intersections within 250 feet
on either side of the main roadway.
(3) Potential for shared access facilities.
(4) Data to demonstrate that the number of driveways proposed is the
fewest necessary.
(5) Support that the access points will provide safe and efficient traffic
operation and be in accordance with Wayne County standards.
(6) Comments shall also be provided on internal circulation design such
as the adequacy of queuing (stacking) at site access points and other
features that may affect traffic operations and safety.
O. Mitigation. The traffic analysis shall outline mitigation measures
and demonstrate any changes to the level of service achieved by these
measures for the proposed future conditions. The mitigated capacity
analysis should be provided in the appendix of the report.
(1) Mitigation shall be provided in order to meet the Township's
goal that all signalized intersections and the bridges leading to
the island operate at a Level of Service C or better during the peak
hours of the day. Unsignalized intersections should operate at Level
of Service D or better.
(2) The mitigation measures may include items such as, but not limited
to:
(a)
Roadway paving or repaving.
(b)
Roadway widening to increase lane width or add additional lanes.
(c)
Change to road intersection alignment or lane configuration.
(d)
Bypass lanes, left turn lanes or deceleration tapers/lanes.
(e)
Changes to traffic control/signalization.
(f)
Relocation change in design, or reduction in number of access
points.
(g)
Reduction in the proposed density or intensity of use.
(3) Sketches should be provided of suggested mitigation. Any alternatives
or suggested phasing of improvements should be described and illustrated.
The responsibility and timing of roadway improvements shall be described.
(4) Proposed mitigation measures shall be provided to the Wayne County
Department of Public Services for review and comment prior to approval
of the traffic analysis. Any mitigation that involves changes to optimize
signal timing must demonstrate that such changes will benefit the
overall operations and will be acceptable to the Wayne County Department
of Public Services.
P. Joint transportation impact studies. A single transportation impact
study may be submitted by two or more applicants where both applicants
submit plans (rezoning, site or subdivision) for sites adjacent or
in close proximity to one another. The transportation impact study
shall conform to all of the requirements of this section, including
an analysis of both sites and all impacted bridges, and intersections.
The transportation impact study shall document the cumulative impact
of both developments.
The following information is required for community impact statements:
A. Existing site conditions. Illustrations and a narrative shall be
provided that describe the characteristics of the site and adjacent
right-of-way. This description should include surrounding land uses,
expected development in the vicinity which could influence future
utility capacity, special site features and a description of any committed
infrastructure improvements.
B. Proposed development. The applicant shall prepare a description of
the proposed development with an enumeration of the square footage
for nonresidential and number of each unit-type for residential development.
Residential equivalent unit figures shall be provided for water for
the new development. The proposed utility system to be constructed
as part of the development shall be detailed on the site plan or subdivision
plat.
C. Wastewater systems. The study shall demonstrate that the proposed
development will be served by adequate public sanitary sewerage. The
public sewerage system shall be considered adequate if there is sufficient
unreserved or uncommitted available capacity to accommodate expected
and ultimate peak flows from the proposed development, and any necessary
improvements shall be constructed and on-line prior to completion
of the development. The analysis of the capacity of the public sewerage
system shall consider the following:
(1) The sewer system's design capacity.
(2) The sewer system's available capacity.
(3) The projected wastewater flow to be generated by proposed new development.
(4) The impact of other proposed projects on the sewer system's
available capacity.
(5) Projects appearing in the Township's Capital Improvements Program
that will affect the ability of the sewer system to serve new development.
(6) Other variables found to have an effect on the ability of the sewer
system to accept the projected wastewater flow from new development.
(7) The sewer system shall be adequate to serve the development. All
lots shall tie into an appropriately sized collector main and shall
not tie directly into an interceptor.
D. Water systems. The study shall demonstrate that the proposed development
will be served by adequate public water. The public water system shall
be considered adequate if the source facilities, storage tanks, pumping
stations and distribution systems have sufficient unreserved or uncommitted
capacity available to provide the pressure and flow required in addition
to minimum fire suppression flow for the proposed development, and
any necessary improvements shall be constructed and on-line prior
to completion of the development. The analysis of the capacity of
the public sewage system shall consider the following:
(1) The water system's design capacity.
(2) The water system's supply source.
(3) The water system's available capacity.
(4) The projected water needs of proposed new development to include
needs for domestic consumption and fire protection.
(5) Adequacy of the proposed system design to provide pressure, flow
and fire suppression, including required looping of water mains.
(6) Existing storage, treatment, and pumping facilities affected by the
proposed development.
(7) The impact of other proposed projects on the water system's
available capacity.
(8) Projects appearing in the Township's Capital Improvements Program
that will affect the ability of the water system to serve new development.
(9) Other variables found to have an effect on the ability of the water
system to satisfy the projected water needs of the new development.
E. Stormwater Management. The study shall demonstrate that the proposed development will provide adequate stormwater management in accordance with Chapter
233, Stormwater Management. The stormwater management plan shall be considered adequate if the development is designed, constructed, and maintained to control runoff, prevent flooding and protect water quality. The analysis of the stormwater management shall consider the following:
(1) Prevention of increased runoff, flood hazards, water pollution related
to stormwater runoff, soil erosion, channel erosion and impact to
downstream properties.
(2) Prevention of impact to wetlands, watercourses or fish and wildlife
habitat.
(3) Stormwater best management practices to decrease runoff velocity,
allow for natural infiltration and passive storage, allow suspended
sediment particles to settle, and to remove pollutants.
(4) Controlled release of stormwater in accordance with the Wayne County design standards and Chapter
233, Stormwater Management.
(5) Stormwater facilities near the Grosse Ile Airport shall not create
an increased bird-aircraft strike hazard.
F. Other utilities. Information shall be provided regarding other utilities
that will be provided to the site, including electricity, gas and
telecommunications. Documentation shall be provided that there is
sufficient electrical capacity to serve the development without impacting
existing uses during peak demand periods.
G. Schools. The study shall demonstrate that there is adequate school
capacity to support the number of dwelling units and that the capacity
of public schools will not be adversely affected by residential development.
School capacity will consider current and projected enrollments, capacities
of individual schools and capacity at each grade level.
H. Recreation. For any residential development, the study shall demonstrate that there is adequate open space and recreation facilities to serve the number of dwelling units proposed. All residential developments shall include neighborhood open space as required by Chapter
238, Subdivision Control.
I. Community character. The study shall demonstrate compatibility with surrounding land uses and adherence to development standards, including landscaping requirements, in accordance with Chapter
285, Zoning. The study shall also demonstrate consistency with the sustainable island character of the Township, as articulated in the Township Master Plan.
J. Environment. The study shall demonstrate that the proposed development will minimize impact to the environmental conditions of the Township, through incorporation of an environmental assessment prepared in accordance with Chapter
98, Environmental Assessment.
K. Township standards. All utilities shall be designed to meet the requirements of Chapter
210, Sewer Use, Chapter
238, Subdivision Control, Chapter
258, Utilities, and other applicable Township engineering standards. Utilities shall be designed and installed with proper access for maintenance by the Township.
L. Phased developments. Where a development is to be constructed in
phases, a phasing plan shall be provided that indicates the improvements
to be completed with each phase. Each phase of a development shall
have all necessary infrastructure installed to fully operate independently
in accordance with the Township engineering requirements, regardless
of whether future phases are constructed.
The following information is required for fiscal impact studies:
A. Existing capita estimate of service costs. The applicant shall determine
existing capita estimate of service costs based upon the most recent
budget provided by the Township. Budgets shall be disaggregated into
categories of service expenditure for general government administration;
public services; police; fire; and recreation. Costs shall be allocated
to residential and nonresidential land uses based upon existing Township
population and employment. Residentially associated costs will be
divided by total population to derive a per capita estimate of service
costs. Nonresidential costs will be divided by local employees for
a per employee estimate of nonresidential service costs.
B. Existing revenues. Existing revenues will be outlined based upon
the most recent budget provided by the Township. Budgets will be disaggregated
into categories of revenue including permit fees, property taxes,
and intergovernmental revenue. Revenues will be allocated to residential
and nonresidential uses, and estimated revenues associated with residential
and nonresidential land uses.
C. Fiscal impact. The applicant shall determine fiscal impact associated
with the development.
(1) The applicant shall outline population and employment changes associated
with the development.
(2) The applicant shall determine infrastructure needs and costs associated
with the development. This shall identify infrastructure facilities
needed to accommodate the development and project the costs of needed
infrastructure improvements.
(3) Total costs to serve the development shall be calculated. Residentially induced costs associated with development shall be calculated by multiplying the per capita estimate of current service costs from Subsection
A above by the population increase of the proposed development. Nonresidential costs associated with development shall be calculated by multiplying the per employee estimate of service costs by the employment increase associated with the development. Annual debt service costs shall also be calculated.
(4) Property taxes, state revenue sharing, utility fees, permit fees
and other revenues associated with the development shall be estimated.
(5) Estimated revenues and costs shall be compared to determine net fiscal
impact on the Township.
D. Marginal costs. The analysis shall also identify any marginal costs
associated with the development. This shall consider surplus capacity
in existing facilities and the point at which new development will
require major expansion to infrastructure and facilities, thereby
making the marginal cost of serving the development higher than the
average per capita cost.
The person(s) responsible for the preparation of the impact
studies shall have a degree or specific professional training in the
preparation of infrastructure and transportation impact studies.
A. The transportation impact assessment/statement preparer shall have
experience in the preparation of transportation impact studies, experience
and familiarity with the Highway Capacity Manual and other traffic
operation evaluation techniques and be one or more of the following:
registered engineer (PE), professional traffic operations engineer
(PTOE) or professional transportation planner (PTP). 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 transportation engineering.
B. The community impact statement shall be prepared by a registered
engineer (PE) with experience in design and construction of utility
systems.
C. The fiscal impact statement preparer shall have demonstrated experience
with accounting, financial analysis, municipal administration or fiscal
analysis.