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Technical Memorandum
To: Chad Millner PE, Director of Engineering
Mark Nolan, AICP, Transportation Planner
City of Edina
From: Chuck Rickart PE, PTOE, Transportation Engineer
Tony Heppelmann PE, Transportation Engineer
Sudheer Dhulipala, Transportation Planner
WSB and Associates, Inc.
Date: April 11, 2016
Re: Edina Southdale Area Model Update and Transportation Study
Project Update
WSB Project No: 1686-670
Introduction/Background
In 2008 WSB assisted the City in the development of a traffic model using the
Synchro/SimTraffic modeling software for the Southeast area (Southdale) of the City. The
study area was bounded by TH 62 (Crosstown) on the north, the Richfield/Edina border on
the east, the Bloomington/Edina border on the south and TH 100 on the west. The model
included 40 signalized intersections, 20 un-signalized intersections, and three
roundabouts.
The purpose in developing the model was to provide a consistent baseline for traffic
analysis and to provide continuously updated results to help gauge the compound effect of
multiple developments in the Southdale area. Since the model was completed, it has been
used by several developers and the City in reviewing the area traffic impacts of proposed
development. Although, the model has been continually updated with traffic characteristics
from approved developments the original traffic conditions were based on 2007 traffic
counts. It is now in need of updating and recalibration with new traffic counts.
Also in 2008 WSB assisted the City in preparation of the Transportation Plan in conjunction
with the Comprehensive Plan update. As part of the Transportation Plan a city wide
transportation planning model was developed for the existing and future land use
projections. Sense the preparation of the land use projections in the Transportation Plan
density changes have occurred in the Southdale area. In addition questions of the
appropriate density have been asked for the area specifically on the west side of France
Avenue.
Southdale Area Model Update and Transportation Plan
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In March of 2015 the City Council appointed a working group that developed the Working
Principles for the France Avenue Southdale Area. These principals will serve as a tool to
guide the development process for the whole Southdale area, and demonstrate methods
that might be used during the Comprehensive Plan update in 2018. In order to provide data
to assist in moving this process to the next stages, development of transportation forecasts
should be completed.
The purpose of this project is to:
1. Update the existing Synchro/SimTraffic traffic model in the Southdale area,
Including expanding the study area to north of TH 62 to W. 60th Street;
2. Updating the CUBE transportation planning model for the entire City, and;
3. Preparation of a transportation analysis for two land use density scenarios for the
Southdale area.
4. Review and analysis of pedestrian/bicycle connections and conflicts in the
Southdale area in relation to the local/regional system.
Figure 1 shows the study area and intersections included with the analysis.
The following sections of this memorandum provide an update on the data collection and
preliminary study results.
Southdale Area Model Update and Transportation Plan
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Figure 1: Study Intersections
Southdale Area Model Update and Transportation Plan
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Existing Traffic Conditions
WSB collected traffic counts at several locations and used traffic counts provided by
Hennepin County and the City of Edina to update the Synchro/SimTraffic models. Traffic
signal timing information was updated based on information provided by Hennepin
County. Lane geometry, new intersections, changes of intersection control and other
information like speed limits were updated based on field visit to all the study
intersections. Figure 2 shows the existing Average Daily Traffic volumes on the adjacent
roadways.
The turning movement counts obtained from the field were input into the
Synchro/SimTraffic model and the SimTraffic model was run for five replications. The
results from the five simulations were then averaged. Figure 3 shows the existing Level of
Service (LOS) at the study intersections.
It should be noted that Roundabouts and Stop Controlled intersections are classified as
unsignalized intersections and have different delay thresholds than signalized intersections
according to the Highway Capacity Manual (HCM).
Southdale Area Model Update and Transportation Plan
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Figure 2: Existing Average Daily Traffic Volumes
Southdale Area Model Update and Transportation Plan
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Figure 3: Existing Level of Service
Southdale Area Model Update and Transportation Plan
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Forecasted 2040 Conditions
The regional Travel Demand Model developed by Metropolitan Council was utilized to
obtain base 2040 forecasts for traffic growth in the area. The models were updated with
projected traffic and the forecasted 2040 level of service was determined at the study
intersections. Subsequently, an alternative analysis was conducted with updated
information on development density in the City’s Transportation Analysis Zones (TAZs) in
the Southdale area. The regional model was rerun with the higher density conditions and
traffic growth rates were estimated for the year 2040 with the higher density
developments in place. Using the growth rates obtained from this alternative, the
Synchro/SimTraffic model was updated to reflect higher traffic forecasts and the Level of
Service under this scenario. Areas of concern were highlighted.
In order to understand the impacts of increasing the density of development in the
Southdale Area, an alternative was analyzed which involved increasing the development
density in future leading to higher number of trips. Table 1 below shows the assumptions
used in this alternative. The increased density was assumed to be in form of number of
households
Table 1: Population and Households Assumptions
These assumptions correspond to trip generation numbers from each zone as shown in
Table 2 below.
Table 2: Change in Number of Trips
TAZ
2040
Population -
Base Scenario
2040 Number of
Households -
Base Scenario
Comp Plan
Average
Density
(Units/Acre)
High Density
Assumption
(Units/Acre)
Increase
Factor
2040
Population -
High
Density
Scenario
2040 Number
Of
Households -
High Density
Scenario
512 2170 1130 21.00 50.00 2.4 5167 2690
513 5060 2610 19.75 48.00 2.4 12298 6343
514 280 130 43.50 100.00 2.3 644 299
515 3110 1550 33.50 65.00 1.9 6034 3007
517 1560 680 22.80 50.00 2.2 3421 1491
518 6470 2910 9.55 14.25 1.5 9654 4342
519 1930 880 10.35 13.25 1.3 2471 1127
Total 20580 9890 39689 19299N/A
Productions Attractions Total Productions Attractions Total
Absolute
Change
Percent
Change
512 11340 18641 29981 20810 24249 45059 15078 50%
513 25413 32107 57520 47950 45611 93561 36041 63%
514 9836 23915 33751 11116 24632 35749 1998 6%
515 14735 19284 34019 24425 24633 49059 15040 44%
517 15669 40355 56024 22234 43488 65722 9698 17%
518 25110 19261 44371 36392 24980 61372 17001 38%
519 9106 11176 20282 11053 12177 23230 2948 15%
2040 Base Scenario 2040 High Density Scenario Total Change
TAZ
Southdale Area Model Update and Transportation Plan
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Figure 4 shows the increase in households and population along with resulting trip
increases from each Transportation Analysis Zone (TAZ).
Figure 4: TAZ Trip Increase Assumptions
Southdale Area Model Update and Transportation Plan
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Figure 5 shows the Average Daily Traffic (ADT) as forecasted by the travel demand model
for the year 2040 base condition.
Southdale Area Model Update and Transportation Plan
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Figure 6 shows the percentage change in ADT as forecasted by the travel demand model
for the year 2040.
Figure 6: Base ADT Percentage Change
Southdale Area Model Update and Transportation Plan
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Figure 7 shows the forecasted 2040 ADT in the high density scenario.
Figure 7: 2040 High Density Scenario ADT
Southdale Area Model Update and Transportation Plan
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Figure 8 shows the percentage change in ADT for the increased density scenario compared
to the 2010 model.
Figure 8: High Density Scenario ADT Percentage Change
Southdale Area Model Update and Transportation Plan
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The turning movement volumes for the PM peak hour in 2040 were estimated based on the
ADT growth percentages derived from the model for various links. The turning movements
were then simulated in the Synchro/SimTraffic network. Figure 9 shows the 2040 Level of
Service assuming growth levels consistent with the 2040 regional travel demand model.
The turning movement volumes for the PM peak hour were adjusted from the base
condition based on the ADT growth percentages derived from the high density scenario
model. Figure 10 shows the Level of Service at the study intersections in the High Density
Scenario assuming no significant improvements to the intersections from current
conditions.
It should be noted that at intersections which do not currently have an LOS F, there may
still be individual movements that are at LOS E or F. Figure 11 shows individual
movements that are at LOS E or F at the study intersections.
Southdale Area Model Update and Transportation Plan
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Figure 9: 2040 Base Level of Service
Southdale Area Model Update and Transportation Plan
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Figure 10: High Density Scenario Level of Service
Southdale Area Model Update and Transportation Plan
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Figure 11: High Density Scenario LOS By Movement
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Summary
Based on the modeling in both the 2040 base scenario and 2040 high density scenario
some traffic issues, with specific movements will exist if no changes are made to the
transportation system. Most of these issues can be addressed by relatively low-cost
improvements such as:
Installation of traffic signals at stop controlled intersections;
Improvements to turning lane geometry, or;
Signal timing
As traffic continues to grow and development is proposed in the area, traffic studies will be
required that will identify specific improvement needs.
Next Steps
The following next steps will be completed.
1. Draft results reviewed by the Edina Transportation Commission (ETC) at their April
20, 2016 meeting.
2. Address issues and concern from ETC and incorporate them into the Draft and Final
reports.
3. With identification of transportation issue areas complete the pedestrian/bicycle
analysis and review.
4. Prepare Draft study report documenting; existing conditions, 2040 development
scenarios, pedestrian/bicycle analysis and identifying issue areas with specific
improvement alternatives.
5. Prepare Final study report based on comments from the Draft report.