Traffic Analysis Report 7-3-08Chanhassen Fairview Medical Center Site Traffic Analysis Chanhassen, Minnesota July 3, 2008 Prepared by Westwood Professional Services, Inc. ????????????????????7??????????????????????????????????4??
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Page 1 INTRODUCTION The purpose of this traffic analysis is to assess the traffic implications of the proposed development on the Fairview Medical Center site in what will be the southeast
quadrant of the Powers Boulevard /T.H. 312 intersection in the City of Chanhassen. The proposed site is presently undeveloped, with Powers Blvd. to be extended south from Lyman Blvd.
to Pioneer Trail with construction of the new T.H. 312 ramps on Powers Blvd. The development location is shown in Figure 1, along with the planned roadway network in the area. The Chanhassen
2005 Alternative Urban Area-Wide Review (AUAR) prepared in 2003 for the City of Chanhassen by the consultant team of Hoisington Koegler Group Inc., Kimley Horn and Associates, Peterson
Environmental Consulting, 106 Group and HDR was used in the determination of background traffic volumes and traffic assignment process. The development is comprised of approximately
65 acres of proposed office and residential land uses, summarized in Table 1 below. It will be built in three phases, the first two of which will construct the medical office building.
Two possible scenarios were considered for Phase 3: a combination of general office and single-family residential or medium-density residential only. A detailed site plan is shown in
Figure 2. Table 1 Land Use Characteristics Phase -Scenario Land Use Size Phase 1 Medical Office Building 88,000 SF Phase 2 Medical Office Building 72,000 SF Phase 3 – Scenario A General
Office 250,000 SF Single-Family Residential 35 DU OR Phase 3 – Scenario B Medium-Density Residential 390 DU Traffic analyses were performed for projected year 2010 volume conditions
(one year after completion of Phase 1), 2012 (one year after completion of Phase 2) and 2020 (one year after full build-out) for Phase 3 – Scenarios A and B. Table 2 Traffic Analysis
Scenarios Year No-Build Phase 1 Phase 2 Phase 3 2010 X X 2012 X X X 2020 X X X X
Page 2 Three intersections were analyzed: Powers Blvd. & the Site Collector road, analyzed for both unsignalized and signalized intersection control and two unsignalized intersections
on the Site Collector road that provide access to the medical office building for Phases 1 and 2 of the development. The proposed roadway geometry is shown in Figure 2. The intersection
of Powers Blvd. and the Site Collector will be the sole access to the development for horizon years 2010 and 2012. (The AUAR assumes that a west leg will be constructed opposite the
site access but no east leg. The east side of the AUAR analysis area ended at Powers Blvd.) There are two site driveways off the Site Collector, the West Site Entrance allowing easy
access to the surface parking to the west of the medical building as well as to the parking ramp and the East Site Entrance providing more direct access to the parking ramp. Along the
south side of the west driveway intersection with the Site Collector, the shoulder is planned to be wide wide enough to allow eastbound through vehicles to by-pass one or two vehicles
waiting for an opportunity to turn left into the medical complex. The internal East Site Entrance is planned to extend to connect with Highway 101 to the east with construction of Phase
3 by 2020.
Page 3 Figure 1 Development Location Site Location
Page 4 Figure 2 Site Plan
Page 5 ANALYSIS OF FUTURE CONDITIONS The future conditions with the development in place were analyzed using a traditional multi-step traffic forecast and analysis process. The major
steps in this process include: determining background traffic volumes, developing trip generation, deriving the direction of approach, assigning site generated traffic to the surrounding
roadway network, analyzing development-related traffic impacts, and establishing mitigation strategies. Analysis Scenarios Traffic analyses were performed for three phases of construction,
the third of which has two potential land use scenarios: Phase 1 – initial construction of the medical office building Phase 2 – completion of medical office building construction Phase
3 – full build-out of the site with the addition of: Scenario A – 250,000 SF office space plus 35 single family detached dwelling units or Scenario B – 390 medium-density residential
condominium /townhouse dwelling units Traffic Volumes To obtain data for assessing operations for Powers Blvd. at the site entrance, background volumes were first developed for the 3
analysis years based on data published in the Chanhassen 2005 AUAR. The AUAR included volume forecasts for the north, south and west legs of the intersection. No forecasts of traffic
were developed for the east leg. (See Appendix Memorandum A-1 for a description of the procedure used to develop the background volumes.) The background volumes are shown for the years
2010, 2012 and 2020 on Figures 5, 6 and 7. Trip Generation The trip generation rates utilized in this study are those documented in the reference book Trip Generation, 7th Edition, 2003,
published by the Institute of Transportation Engineers (ITE). Table 3 summarizes the weekday daily, A.M. peak hour and P.M. peak hour trip rates utilized for this study.
Page 6 Table 3 Trip Generation Rates I.T.E. Code Land Use Per Rates Distribution Daily A.M. P.M. A.M. % In A.M. % Out P.M. % In P.M. % Out 720 Medical Office Building KSF 36.13 2.48
3.72 79 21 27 73 710 General Office Building KSF 11.01 1.55 1.49 88 12 17 83 210 Single-Family Detached Housing DU 9.57 0.75 1.01 25 75 63 37 230 Condominium /Townhouse DU 5.86 0.44
0.52 17 83 67 33 Table 4 summarizes the overall gross trip generation. No reductions were taken for internallycaptured, multi-purpose or pass-by trips for the proposed office and residential
land uses. Table 4 Gross Trip Generation Phase Land Use Approx. Dev. Units Trips A.M. In A.M. Out A.M. Total P.M. In P.M. Out P.M. Total Daily Total 1 Medical Office Bldg. 88 KSF 172
46 218 88 239 327 3,180 2 Medical Office Bldg. 72 KSF 141 38 179 72 196 268 2,602 Total, Phases 1 & 2 313 84 397 160 435 595 5,782 3 Scenario A General Office Bldg. 250 KSF 341 47 388
63 310 373 2,754 Single-Family Det. Housing 35 DU 7 19 26 22 13 35 336 Total, Phases 1, 2 & 3-A 661 150 811 245 758 1,003 8,872 Or Scenario B Condominium /Townhouse 390 DU 29 142 171
136 67 203 2,286 Total, Phases 1, 2 & 3-B 342 226 568 296 502 798 8,068
Page 7 Trip Distribution A large percentage of traffic generated from the development area will utilize T.H. 312 to the east and west and Powers Blvd. to the north and south. With construction
of Phase 3, traffic generated here will also utilize the connection of the Site Collector road through to Highway 101 to the east. This trip distribution, or direction of approach, for
the development traffic is shown on Figure 3 for Phases 1 and 2 and on Figure 4 for the Phase 3 scenarios. This distribution is based on data contained in the AUAR and traffic patterns
expected in the area. The majority of Phase 3 traffic is expected to be oriented towards Highway 101. Trip Assignment and Traffic Analysis In the trip assignment portion of the analysis,
the new trips generated from the development area were assigned to the roadway network using the routing patterns expected to be employed by the future employees, visitors and residents.
The organization and tabulation of the trip assignment was facilitated by use of an Excel spreadsheet designed to carry out the traffic assignment process across the study area network.
Total trips – background traffic plus site-generated trips – for each of the four analysis cases are shown on Figures 5 through 8. Timeframes for Traffic Assignment Traffic analyses
were performed for the A.M. and P.M. peak hours for 2010 (one year after opening of the initial phase of construction of the medical office building), 2012 (one year after opening of
Phase 2 of the medical office building) and 2020 (one year after full build-out).
Page 8 Figure 3 Trip Distribution – Phases 1 & 2 76% 24%
Page 9 Figure 4 Trip Distribution – 2020 with Connection to Highway 101 73% /23% 22% /7% 5% /70% Key: Phases 1 & 2 /Phase 3
Page 10 Powers Blvd. and Site Collector A series of A.M. and P.M. peak hour traffic analyses were conducted for the three study intersections using the planned roadway geometry and stop-sign
intersection control for the four analysis cases in 2010, 2012 and 2020. (Volumes for each of the analysis cases are shown on Figures 5, 6 and 8.) Analyses were first performed for the
A.M. and P.M. peak hour No-Build conditions for the Powers Blvd. /Site Collector intersection. These No-Build volumes are shown on Figures 5 through 8. Results are shown on Table 5 below,
which shows the average seconds of delay per vehicle along with the corresponding Level of Service (LOS) for the critical stopped movement at the intersection. (Appendix Table A-1 shows
the LOS letter grades with their corresponding levels of delay. Results for all intersections in all scenarios are shown by movement in Appendix Tables A-2 – A-4.) In addition, analyses
were performed for the four Build cases. No-Build conditions resulted in LOS B or C for all three analysis years. With construction of Phase 1, the eastbound left movement for traffic
generated by the development to the west of Powers Blvd. across from the Chanhassen Fairview Medical Center site is projected to experience LOS “E” in the A.M. peak hour and LOS “F”
in the P.M. peak hour. For Phase 2, LOS “E” is projected for both the eastbound and westbound left turns in the A.M. peak hour, while LOS “F” is projected in the P.M. peak hour. LOS
“F” is projected for both left turn movements for all subsequent phases with this intersection under stop sign control. Based on the results of stop sign analysis of the forecasted traffic
volumes, a traffic signal will be required when traffic volumes reach Phase 2 levels in order to safely accommodate left turners exiting the site. Further analysis was conducted for
this intersection with signal control in place. As shown in Table 6, results are LOS “B” or borderline “B-C” for all scenarios under those conditions.
Page 11 Table 5 Powers Blvd & Site Collector Stop Sign Controlled Intersection Analysis Critical Movement LOS (1) Analysis Scenario West Leg (Critical Movement: Eastbound Left) East
Leg (Critical Movement: Westbound Left) A.M. Peak Hour P.M. Peak Hour A.M. Peak Hour P.M. Peak Hour 2010 No-Build 15 /B-C (2) 21 /C N/A N/A 2010 Phase 1 48 /E 101 /F 36 /E 32 /D 2012
No-Build 15 /B-C (2) 21 /C N /A N /A 2012 Phases 1 & 2 39 /E (3) /F 46 /E 136 /F 2020 No-Build 18 /C 23 /C N /A N /A 2020 Phases 1, 2 & 3-A (3) /F (3) /F (3) /F (3) /F 2020 Phases 1,
2 & 3-B (3) /F (3) /F 138 /F (3) /F Key: NN.N /X = Delay in Seconds per Vehicle /Level of Service (1) Delay and LOS were determined by the SimTraffic analysis program; results are rounded
to the nearest whole number (2) Delay value as rounded to the nearest whole number falls at the threshold between 2 LOS ratings (3) SimTraffic does not calculate realistic delay when
intersection is highly overloaded Table 6 Powers Blvd & Site Collector Signalized Intersection Analysis Analysis Overall Intersection LOS (1) Analysis Scenario A.M. Peak Hour P.M. Peak
Hour 2010 Phase 1 11 /B 15 /B 2012 Phases 1 & 2 14 /B 17 /B 2020 Phases 1, 2 & 3-A 16 /B 20 /B-C (2) 2020 Phases 1, 2 & 3-B 14 /B 18 /B Key: NN.N /X = Delay in Seconds per Vehicle /Level
of Service (1) Delay and LOS were determined by the Synchro analysis program; results are rounded to the nearest whole number (2) Delay value as rounded to the nearest whole number falls
at the threshold between 2 LOS ratings Internal Site Driveways Analyses conducted for the internal site driveways show that they will be able to function well under all scenarios. LOS
results, shown in Tables 7 and 8 below, are primarily “A” and “B” in both peak hours, with a borderline “B-C” in the P.M. peak hour for the West Site Access under Phase 3 – Scenario
A conditions.
Page 12 Table 7 Site Collector & West Site Access Stop Sign Controlled Intersection Analysis Critical Movement LOS (1) Analysis Scenario Critical Movement A.M. Peak Hour P.M. Peak Hour
2010 No-Build N /A N/A 2010 Phase 1 SBR 2 /A 3 /A 2012 No-Build N /A N/A 2012 Phases 1 & 2 SBR 2 /A 4 /A 2020 No-Build N /A N/A 2020 Phases 1, 2 & 3-A SBL 15 /B-C (2) 11 /B 2020 Phases
1, 2 & 3-B SBL 6 /A 8 /A Key: NN.N /X = Delay in Seconds per Vehicle /Level of Service (1) Delay and LOS were determined by the SimTraffic analysis program; results are rounded to the
nearest whole number (2) Delay value as rounded to the nearest whole number falls at the threshold between 2 LOS ratings Table 8 Site Collector & East Site Access Stop Sign Controlled
Intersection Analysis Critical Movement LOS (1) Analysis Scenario Critical Movement A.M. Peak Hour P.M. Peak Hour 2010 No-Build N /A N/A 2010 Phase 1 SBR 2 /A 3 /A 2012 No-Build N /A
N/A 2012 Phases 1 & 2 SBR 3 /A 4 /A 2020 No-Build N /A N/A 2020 Phases 1, 2 & 3-A SBL 4 /A 9 /A 2020 Phases 1, 2 & 3-B SBL 10 /A-B (2) 6 /A Key: NN.N /X = Delay in Seconds per Vehicle
/Level of Service (1) Delay and LOS were determined by the SimTraffic analysis program; results are rounded to the nearest whole number (2) Delay value as rounded to the nearest whole
number falls at the threshold between 2 LOS ratings QUEUEING ANALYSIS A queue length analysis was performed using SimTraffic for intersection approaches of interest. The analysis was
conducted to determine whether the 95th percentile queues would be accommodated in the available storage for turn lanes and between the driveways and intersections. The 2020 worst-case
scenario was tested, with the total volumes forecasted for Phases 1, 2 and 3-A.
Page 13 As shown in Table 9, the available storage was adequate for all movements in the worst case scenario. Table 9 95th Percentile Queue Length Analysis (1) 2020 Phase 3 – Worst-Case
Scenario A Location Powers Blvd. & Site Collector Site Collector & West Site Entr. Site Collector & East Site Entr. Movement Southbound Left Northbound Right Westbound Left-Through Westbound
Right Southbound Eastbound Left-Through Eastbound Through Westbound Southbound Eastbound Westbound Available Storage 270 290 215 215 200+ 30 215 138 200+ 138 200+ A.M. Peak Hour 217
36 46 32 42 46 26 4 41 39 3 P.M. Peak Hour 155 35 102 100 77 47 24 4 62 9 0 (1) Queue lengths determined by SimTraffic analysis program; lengths are given in feet .
Appendix Memorandum A-1 Development of Background Volume Estimates Tables A-1 Key to Intersection Level of Service Grades A-2 Capacity Analysis Results by Movement – Powers Blvd. & Site
Collector A-3 Capacity Analysis Results by Movement – Site Collector & West Site Entrance A-4 Capacity Analysis Results by Movement – Site Collector & East Site Entrance
Memorandum A-1 March 24, 2008 Development of Background Volume Estimates for Erhart Property Traffic Study The “Total” (Build) volumes from the “Chanhassen 2005 AUAR” Traffic Study,
published in 2003 by Kimley-Horn were used as the basis for the No-build volumes in the Erhart property study. The following information was included within the Kimley-Horn study (which
assumed no development on the Erhart property): • 2010 Build AM and PM peak hour turning movement volume estimates at the intersection of Powers Boulevard and Site Entrance • 2010 Build
ADT volume estimates for the west and south legs of this intersection. In addition, the Metropolitan Council year 2030 ADT estimate for the south leg of the intersection was also noted.
The missing information that must be estimated includes: • Daily (24-hour) turning movement estimates for all movements involving the west leg. These turning movement volumes will remain
constant through all design years of the Erhart property traffic study since 100% build out of the Chanhassen 2005 AUAR property is anticipated by 2010. • Estimates of daily northbound
and southbound through traffic for 2012, 2020, and 2030, the three design years for the Erhart property study. • 2012, 2020, and 2030 ADT estimates for the north leg. • 2012 and 2020
ADT estimates for the South leg (2030 was provided by Met Council as noted above). To develop these volume estimates, the following process was administered: 1. Daily turning movements
and K-Factors (percentage of daily traffic occurring during the peak hour) were calculated (for movements to and from the west leg only) for the AM and PM peak hours using the peak hour
turning movement and west leg ADT volume data provided. Separate K-Factors were calculated for the AM and PM peak hours. Complementing movements (EBL/SBR and EBR/NBL) were averaged in
order to normalize the daily directional distribution at 50/50 to/from the site. 2. For the south leg, where a 2010 Total (Build) ADT estimate was provided, K-Factors for northbound
and southbound through traffic were calculated using the K-Factors for site traffic developed in step 2. The same K-Factor for northbound and southbound through traffic was assumed for
the AM and PM peak hours. 3. Using the K-Factor calculated for the northbound and southbound movements in step 2, along with the site traffic K-Factors from step 1, the 2010 Total (Build)
ADT for the north leg was calculated. 4. The 2030 ADT for the north leg was calculated by assuming the same ratio between north and south leg for 2030 ADT as for 2010 ADT. 5. 2012 and
2020 ADT estimates for the north and south legs were estimated by linear interpolation between years 2010 and 2030. 6. Daily northbound and southbound through volume estimates for 2010
were developed using the K-factors calculated in step 3, then normalizing the results to provide a 50/50 directional distribution. 7. Daily northbound and southbound through volume estimates
for 2012, 2020 and 2030 were developed by factoring the 2010 estimates by the ratios calculated in step step 5.
Table A-1 Key to Intersection Level of Service Grades LOS ABCDEF LOS ABCDEF >50 Signalized Intersections Unsignalized Intersections Control Delay Per Vehicle (in seconds) 10 >10 and
15 >15 and 25 >35 and 55 >25 and 35 >35 and 50 Control Delay Per Vehicle (in seconds) >55 and 80 >80 10 >10 and 20 >20 and 35
Capacity Analysis Results by Movement Signalized Intersections (1) Right Right Left Thru-Thru Right Left Thru-Thru Right Phase 1 21 /C 16 /B 44 /D 7 /A 3 /A 45 /D 6 /A 1 /A 11 /B Phase
2 21 /C 15 /B 44 /D 11 /B 3 /A 44 /D 6 /A 1 /A 14 /B Phase 3 -Scenario A 21 /C 14 /B 48 /D 16 /B 4 /A 40 /D 6 /A 1 /A 16 /B Phase 3 -Scenario B 21 /C 15 /B 44 /D 10 /A-B (2) 3 /A 44
/D 6 /A 1 /A 14 /B Phase 1 8 /A 7 /A 42 /D 11 /B 5 /A 44 /D 7 /A 3 /A 15 /B Phase 2 8 /A 7 /A 42 /D 14 /B 5 /A 45 /D 7 /A 3 /A 17 /B Phase 3 -Scenario A 7 /A 8 /A 46 /D 19 /C 6 /A 45
/D 9 /A 4 /A 20 /B-C (2) Phase 3 -Scenario B 8 /A 7 /A 46 /D 15 /B 5 /A 45 /D 7 /A 3 /A 18 /B Key: NN.N /X = Delay in Seconds per Vehicle /Level of Service (1) Delay and LOS were determined
by the Synchro analysis program; results are rounded to the nearest whole number P.M. Peak Hour A.M. Peak Hour Peak Volume Scenario Eastbound Site Access Westbound Site Collector 45
/D 50 /D 45 /D 39 /D 41 /D 44 /D 44 /D 34 /C Northbound Powers Blvd. Southbound Blvd. Table A-2 Powers Blvd. & Site Collector (2) Delay value as rounded to the nearest whole number falls
at the threshold between 2 LOS ratings Overall Left-Thru Intersection 43 /D 43 /D 43 /D 44 /D 47 /D 50 /D 51 /D 50 /D Left-Thru
Capacity Analysis Results by Movement Unsignalized Intersections (1) Left Thru Thru Right Left Right Phase 1 2 /A 1 /A 0 /A N /A N /A 2 /A 2 /A Phase 2 2 /A 2 /A 0 /A N /A N /A 2 /A
2 /A Phase 3 -Scenario A 2 /A 2 /A 0 /A 0 /A 15 /A-B (2) 3 /A 2 /A Phase 3 -Scenario B 3 /A 2 /A 0 /A 0 /A 6 /A 2 /A 2 /A Phase 1 2 /A 1 /A 0 /A N /A N /A 3 /A 2 /A Phase 2 3 /A 2 /A
1 /A N /A N /A 4 /A 2 /A Phase -5 /A 2 /A 1 /A 0 /A 11 7 /A 3 /A Table A-3 Site Collector & West Site Entrance Eastbound Westbound Northbound Southbound Overall Intersection Peak Volume
Scenario Peak Hour A.M. Peak Hour 3 Scenario A /B Phase 3 -Scenario B 3 /A 1 /A 1 /A 0 /A 8 /A 4 /A 2 /A Key: NN.N /X = Delay in Seconds per Vehicle /Level of Service (1) Delay and LOS
were determined by the SimTraffic analysis program; results are rounded to the nearest whole number (2) Delay value as rounded to the nearest whole number falls at the threshold between
2 LOS ratings P.M. P
Capacity Analysis Results by Movement Unsignalized Intersections (1) Left Thru Thru Right Left Right Phase 1 2 /A N /A N /A 2 /A 2 /A Phase 2 2 /A N /A N /A 3 /A 2 /A Phase 3 -Scenario
A 2 /A 2 /A 0 /A 0 /A 4 /A 3 /A 2 /A Phase 3 -Scenario B 2 /A 2 /A 0 /A 0 /A 10 /A-B (2) 3 /A 2 /A Phase 1 2 /A N /A N /A 3 /A 3 /A Phase 2 2 /A N /A N /A 4 /A 3 /A Phase -3 /A 2 /A
0 /A 0 /A 9 /A 5 /A 2 /A Peak Hour A.M. Peak Hour N /A Southbound Site Collector & East Site Entrance Eastbound Westbound Northbound Overall Intersection N /A Table A-4 N /A N /A Peak
Volume Scenario 3 Scenario A Phase 3 -Scenario B 2 /A 1 /A 0 /A 0 /A 6 /A 4 /A 3 /A Key: NN.N /X = Delay in Seconds per Vehicle /Level of Service (1) Delay and LOS were determined by
the SimTraffic analysis program; results are rounded to the nearest whole number (2) Delay value as rounded to the nearest whole number falls at the threshold between 2 LOS ratings P.M.
P