Carver County TrafficImpact Analysis process
Appendix A
Traffic Impact Analysis Process
I. Introduction
The purpose of this process is to provide guidance to applicants assessing the potential transportation
impacts of a new development or a redevelopment. The following guidelines have been developed to
provide a clear, orderly, and consistent analysis by establishing minimum standards for all Traffic Impact
Analysis (TIA). County staff will review the TIAs based on these criteria.
II. Transportation Impact Analysis (TIA)
A TIA is a study which assesses the effects that a particular development will have on the transportation
network in the community. These studies vary in their range of detail and complexity depending on the
type, size and location of the development. TIAs should accompany developments which have the
potential to impact the transportation network. It will be determined in the early review meeting if a TIA
is necessary. These studies can be used to help evaluate whether the development is appropriate for a
site and what type of transportation improvements may be necessary. For the purposes of the TIA, all
land at one location, including existing developments or available land for building development under
common ownership or control by an applicant shall be considered when determining if required criteria
are met. An application shall not avoid the intent of this criterion by submitting a partial or segmented
application or approval request for building permits, development plans, subdivision, etc.
III. Transportation Impact Analysis Triggers
a) A TIA is required for any development meeting any of the following criteria:
i) generating approximately 750 or more vehicle trips per day.
ii) generating approximately 100 or more vehicle trips in any one hour period.
iii) if associated roadway traffic is increased by 50% or more.
iv) development will likely create a hazard to public safety.
v) development traffic will substantially affect an intersection or roadway segment already
identified as operating at an unacceptable level of service as determined by the County.
The trip rates in the most current edition of the Institute of Transportation Engineers (ITE) Trip
Generation should be used in determining the amount of traffic a particular development will generate.
If the proposed use is an expansion of an existing facility then existing traffic patterns should be
extrapolated to the proposed improvement. If no ITE rates exist for a particular type of development or
there is some uncertainty regarding the need to conduct a study, the County Traffic Engineer will
determine if a TIA is required. If an applicant believes a TIA is not necessary then a written justification
will be required. County staff will review the document and determine how to proceed.
b) A TIA is not required when a development falls below the above mentioned threshold.
A traffic study may be required in lieu of a TIA.
Carver County will consider the following effects in the evaluation of traffic studies that are
warranted by certain zoning, land‐use, conditional use permits and final development plan
applications prior to the application being submitted:
i) Does the development significantly affect the operation and congestion of the adjacent
roadways or intersections and/or result in a traffic hazard?
ii) Does the development significantly affect pedestrian safety?
iii) Does the development provide feasible opportunities to address an existing traffic issue or
safety problem?
c) Sound engineering practices and applicable regulatory standards shall be used to evaluate any
development proposal, regardless of the development size or scope.
d) Developments adjacent to another jurisdictional entity shall submit the traffic study to the
respective agency for their information.
IV. Transportation Impact Analysis Study Area
a) The transportation consultant and project manager shall meet with the County Traffic Engineer to
establish the study area, to discuss critical issues, and to determine the complexity of the report to
be submitted. A preliminary site plan showing the planned development, internal circulation, and
connection to the public roadway system shall be provided to the County at the initial meeting. The
study area shall be approved by County staff.
b) All site access drives, adjacent roadways, and adjacent major intersections, plus the first affected
signalized intersection in each direction from the site shall be analyzed. Additional areas may be
added based on development size and specific site or local issues and policies. A general guideline
for setting the project study boundary will be when a development’s traffic using any particular
intersection falls below 20%.
V. Transportation Impact Analysis Requirements
A TIA shall be completed by a qualified Professional Engineer (P.E.). All traffic analysis shall utilize
software consistent with MnDOT practice such as the latest versions of Synchro/SimTraffic and for
roundabouts SIDRA or ARCADY. The TIA report will usually include the following:
a) Report Letter
i) Identify the person(s) to whom the report is addressed.
ii) Summarize the findings and recommendations.
iii) Clearly define peak traffic periods.
b) Proposed Development and Study Area.
i) Describe proposed development.
ii) Map of site and street network.
iii) Identify intersections/highway links to be analyzed.
c) Existing Traffic Conditions
i) Figures showing ADTs, peak hour turning movements and levels of service (for all applicable
peak hour and peak hour of development unless otherwise directed by the County Traffic
Engineer).
ii) Indicate roadway/intersection geometrics, street right‐of‐way, type of traffic control at
intersections, traffic regulations (i.e. no parking zones, posted speed limit), and bus stops.
iii) Determine queue lengths at controlled intersections that may affect project.
d) Future Projected Traffic Conditions Without Development (Utilize County Travel Demand Model or
historical growth information)
i) Figures showing future projected ADTs, peak hour turning movements and level of service.
ii) Identify changes in road network and land use expected under full development conditions.
iii) Determine queue lengths at controlled intersections that may affect project.
e) Existing Site Traffic
i) Site‐generated traffic – ADT and peak hours.
ii) Figure showing distribution by direction of approach.
iii) Figure showing assignment (volumes and turning movements) to each link in the network
analyzed.
f) Proposed Site Traffic
i) Site‐generated traffic – ADT and peak hours (if development is to be completed in phases, show
cumulative traffic for each phase added)
ii) Figure showing distribution by direction of approach.
iii) Figure showing assignment (volumes and turning movements) to each link in the network
analyzed.
iv) "Pass‐by" trip assumptions, distribution and assignment.
g) Traffic Impact of Proposed Development
i) Figures showing ADTs, peak hour turning movements and level of service for present conditions
with proposed development.
ii) Figures showing ADTs, peak hour turning movements and level of service for future projected
conditions with proposed development.
iii) Determine queue lengths at controlled intersections that may affect the project.
iv) Review ingress/egress sight distance, capacity and safety.
v) Review on‐site circulation for vehicles and pedestrians.
h) Problem Areas
i) Identify congestion or safety problems for present conditions with proposed development.
ii) Identify congestion or safety problems under full development conditions with proposed
development.
iii) Identify crash experience and expectancy.
i) Travel Demand Management Plan
i) A travel demand management plan shall be included as part of the analysis
ii) Bicycle and Pedestrian Facilities (provide for access to, from and through development for
bicyclists and pedestrians; recommend designated bicycle paths, lanes and facilities)
j) Recommended Improvements and Mitigation Measures
i) Identify possible short‐term improvements and mitigation measures.
ii) Identify possible long‐term improvements and mitigation measures
iii) Recommended improvements and mitigation measures
k) Appendices
i) Capacity analysis calculations, data and assumptions (provide sufficient information for reviewer
to follow analysis and to be able to spot check results).
ii) Queue length analysis calculations, data and assumptions.
iii) Provide other pertinent information that may be needed to explain or justify data used in the
report (i.e., if data from an actual field study of sites in the metro area is used in place of ITE trip
generation rates, then a report of the field study results should be included in the appendix)
The TIA must be submitted at the same time as the appropriate development application to the City.
However, the developer may find it advantageous to have the TIA completed and submitted to the County
several weeks prior to the submittal of the development application in order to incorporate
recommendations from the traffic report on the development plan. The completed TIA meeting the above
requirements will be reviewed by County staff and written comments will be provided within 30 days.