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
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.
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)
intersection traffic signals and configuration
traffic signal progression
percentage of heavy trucks
adjacent access point locations
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
