Traffic Impact Study
Requirements
Planning & Zoning Department, 395 Third Street, Manistee, MI 49660 | 231.723.6041 (phone)
Special Studies or Research
For complex site plans and/or for land uses that may generate significant impacts on surrounding land uses
or public facilities, the Zoning Administrator or Planning Commission may require any or all of the following
reports or studies as a part of a complete site plan.
Property Information
Address:
Parcel #
Applicant/Preparer Information
Name of Owner or Lessee:
Address:
Phone #:
Cell#:
e-mail:
Name of Preparer
Address:
Phone #:
Cell#:
e-mail:
License Number:
Expiration Date:
Project Information
Description of Project:
Description
A traffic impact study shall include an analysis of the existing traffic conditions on the roadway network in the
vicinity of a proposed project, including any accident history, average speeds, average daily and peak hour traffic
volumes and levels of service of all key roadway segments and intersections. The study shall further indicate the
effect of a proposed development on adjacent roadways and intersections and indicate the anticipated points of
origin, direction and volume of traffic flow to and from the proposed development. The study shall be prepared
by either a registered professional engineer (P.E.) or transportation planner with at least five (5) years of experience
preparing traffic impact studies in Michigan. The study shall include a summary of the qualifications and
documented experience of the author and specifically describing experience in preparing traffic impact studies in
Michigan. If the traffic impact study involves geometric design recommendations, the study shall be prepared or
supervised by a registered engineer with a strong background in traffic engineering.
Criteria for Requiring a Traffic Impact Study
The Zoning Administrator or Planning Commission may require that a traffic impact study be prepared as an
attachment to a site plan for any proposed commercial, industrial, residential or mixed use development which has
the potential to significantly increase traffic volumes on the surrounding roadway network. In determining the
level of potential impact, the Zoning Administrator or Planning Commission shall consult appropriate planning and
engineering texts including, but not limited to, Trip Generation, published by the Institute of Transportation
Engineers and may seek the counsel of other professionals with experience with developments similar to that
proposed. A traffic impact study may be required under this section when, in the judgment of the Zoning
Administrator or Planning Commission, the proposed development will result in an increase of either the average
daily traffic or the peak hour traffic equal to or greater than ten percent (10%) of the current traffic volume on the
adjoining roadway.
Outside Review
The Zoning Administrator may be provided to the City Engineer, Planner and/or an independent traffic engineer or
transportation planner to review and comment on any traffic impact study prepared pursuant to this Section. The cost
of any such review shall be borne by the applicant.
(5/19)
Required Study Content
In general, a required traffic impact study shall document existing conditions on the existing roadway network including
all intersections within one (1) mile of the proposed development including average daily traffic and peak hour volumes
in all directions, existing turning movements, levels of service, average traffic speeds and accident history. Existing
pedestrian and non-motorized traffic volumes shall also be estimated. The traffic impact study shall project the impact
of the proposed development on the roadway network including all intersections within one (1) mile of the proposed
development including projected average daily traffic and peak hour volumes in all directions, anticipated turning
movements and anticipated levels of service. Anticipated impacts on pedestrian and non-motorized traffic volumes shall
also be projected
Waived
Initials
The following specific elements shall be addressed in a required traffic impact study, unless
specifically waived by the Zoning Administrator or Planning Commission:
A narrative summary at the beginning of the report, including, but not limited to:
The applicant and project name.
A location map.
The size and type of development.
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).
Project phasing identifying the year of development activities per phase and proposed access plan
for each phase.
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:
peak-hour volumes (existing and projected)
number of lanes
cross-section
intersection traffic signals and configuration
traffic signal progression
percentage of heavy trucks
adjacent access point locations
jurisdiction
grades
Plan showing proposed roadway per phase for each access. Driveway design and roadway
improvements shall meet Michigan Department of Transportation (MDOT) or City of Manistee
standards and guides.
Capacity analysis shall be performed at each access point. The City’s preference is the use of
Highway Capacity Software, (HCS 2000), or a later version thereof. 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
one (1) mile of an existing signalized intersection shall be analyzed in coordination with the existing
signal timing. A time-space diagram should also be included.
A traffic impact study shall include an analysis of conditions with and without the proposed
development on the existing system, and with the proposed development for both existing and
projected traffic volumes. The traffic volumes for the development shall assume a total build out.
The completed analysis shall be summarized in a table showing all the Measures of Effectiveness
(MOE) for all of the above conditions.
Required operational changes shall be part of the site plan review and any access permit approval
process.
Evaluation and Criteria. As general criteria, the existing roadway network and all access points to a proposed
development shall be demonstrated to be fully capable of accommodating the increased average and peak hour traffic
anticipated. In the event the anticipated level of service on any roadway segment or intersection is shown to decline,
the traffic impact study shall present alternative approaches proposed to manage anticipated traffic without such
decline.
Preparers Signature: ____________________________________________Date: ______________________
Traffic Study Requirements Page 2 of 2