HomeMy WebLinkAboutTraffic Impact Analysis rec'd 4-18-11 e c
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A ENGINEERING CO LLC
William J. Fehribach P.E. 8365 Keystone Crossing, Suite 201
PRESIDENT Indianapolis, In 46240
Steven J. Fehribach, P.E. (317) 202 -0864 fax (317) 202 -0908
ig VICE PRESIDENT
MEMORANDUM
DATE: 1/19/2011
TO: Charlie Frankenberger
Nelson Frankenberger, PC
FROM: Steven J. Fehribach, P.E.
Amanda Johnson, E.I.
RE: Traffic Impact Analysis
116 Street Spring Mill Road
Comparison of Residential Uses and Proposed Development Uses
A complete Traffic Impact Analysis was performed for a proposed development that is to be located
south of 116 Street between Spring Mill Road and Illinois Street in Carmel, Indiana. The proposed
development was divided into three phases with the final phase including every land use within the
proposed development site plan. The total build out of the site, as proposed, will include retail,
office and residential and uses. Within this memorandum, only Phase III of the proposed
development (total build out) will be referenced. Currently, this site is zoned for single family
residential land uses with a density of 2.4 dwelling units per acre. This memorandum will include a
traffic impact comparison between the proposed development and the site that would exist with full
build out under existing zoning.
Intersection Analysis
A capacity analysis was performed using the recognized computer program Synchro in order to
determine the effects of the residential land uses and the proposed development on the existing
intersections. Five scenarios were examined:
Scenario I: Existing Traffic Volumes
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Scenario 2: Existing Traffic Volumes Residential Traffic Volumes
Scenario 3: Existing Traffic Volumes Proposed Development Traffic Volumes
Scenario 4: Year 2020 Traffic Volumes Residential Traffic Volumes
Scenario 5: Year 2020 Traffic Volumes Proposed Development Traffic Volumes
The intersection of Spring Mill Road and 116 Street currently exists as a one -lane roundabout with
a westbound right -turn bypass lane. The existing traffic volumes operate below acceptable levels of
service with the existing one -lane roundabout. Therefore; Scenario 2 through Scenario 5 include
converting the existing one -lane roundabout to a two -lane roundabout. This improvement is the
minimum improvement necessary for the existing traffic volumes to meet minimum level of service
requirements set forth by the City of Carmel.
The intersection of Illinois Street 116 Street currently exists as a two -lane roundabout and all
approaches operate above acceptable levels of service during the AM peak hour and the PM peak
hour. When the generated traffic volumes from the residential land uses are added to the existing
traffic volumes and the projected year 2020 traffic volumes, all approaches at this intersection
continue to operate above acceptable levels of service. However, when the traffic volumes from the
proposed development are added to the existing traffic volumes and the projected year 2020 traffic
volumes, some approaches operate below acceptable levels of service and improvements are
necessary. In order to obtain acceptable levels of service during the peak hours for Scenario 3
traffic volumes, the following improvements are necessary:
The addition of a northbound right -turn bypass lane.
In order to obtain acceptable levels of service during the peak hours for Scenario 5 traffic volumes,
the following improvements are necessary:
The addition of a northbound right -turn bypass lane.
The addition of a westbound right -turn bypass lane.
The intersection of 111 Street. and Spring Mill Road currently exists as a one -way stop control and
all approaches operate at or above acceptable levels of service. When traffic volumes from either
the residential land uses or the proposed development land uses are added to the existing traffic
volumes, improvements will be necessary to meet the minimum level of service standards set forth
by the City of Carmel. The acceptable levels of service can be achieved if a one -lane roundabout is
constructed; however, the southbound approach may need two entry lanes to accommodate heavy
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southbound traffic volumes and to prevent queuing into the adjacent intersection to the north. In
addition, when Illinois Street is constructed to 103 Street, as per the Comprehensive Plan, traffic
volumes will likely divert to Illinois Street and it can be expected that with the reduction in traffic
volumes along Spring Mill Road, acceptable levels of service will be achieved at the intersection of
111 Street and Spring Mill Road without the implementation of a roundabout.
Conclusions
A preliminary capacity analysis has shown that the same improvements will be necessary at the
intersections of 111 Street Spring Mill Road and 116 Street Spring Mill Road for both the
proposed development traffic volumes and the residential traffic volumes. Improvements are
necessary at the intersection of 116 Street Illinois Street when considering generated traffic
volumes from the proposed development, but no improvements are necessary at this intersection
when considering generated traffic volumes from the residential land uses as described in the
Comprehensive Plan.
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