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CC - Traffic Impact Study - 5.19Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho Page i Table of Contents EXECUTIVE SUMMARY .......................................................................................................................... 1 Introduction .............................................................................................................................................. 1 Proposed Development ............................................................................................................................. 1 Study Area ................................................................................................................................................ 1 Conclusions .............................................................................................................................................. 1 INTRODUCTION ........................................................................................................................................ 2 PROPOSED DEVELOPMENT .................................................................................................................... 3 STUDY AREA CONDITIONS .................................................................................................................... 3 Study Area ................................................................................................................................................ 3 Land Use ................................................................................................................................................... 3 STUDY PERIOD .......................................................................................................................................... 4 Build Out Year.......................................................................................................................................... 4 Time Period .............................................................................................................................................. 4 EXISTING CONDITIONS ........................................................................................................................... 4 Road System ............................................................................................................................................. 4 System Improvements .............................................................................................................................. 4 Traffic Volumes ........................................................................................................................................ 4 Accident Analysis ..................................................................................................................................... 6 PROJECTED TRAFFIC ............................................................................................................................... 6 Background Traffic ................................................................................................................................... 6 Off Site Traffic ......................................................................................................................................... 6 Trip Generation......................................................................................................................................... 8 Trip Distribution ....................................................................................................................................... 8 Site Traffic ................................................................................................................................................ 9 Total Traffic ............................................................................................................................................ 10 TRAFFIC ANALYSIS ............................................................................................................................... 11 Capacity Analysis and Level of Service ................................................................................................. 11 Intersection Analysis .............................................................................................................................. 11 Roadway Analysis .................................................................................................................................. 12 Site Access .............................................................................................................................................. 12 DISCUSSIONS ........................................................................................................................................... 12 Approved Land Use ................................................................................................................................ 12 Roadway Improvements ......................................................................................................................... 13 Required Due to Existing Traffic Conditions ..................................................................................... 13 Required Due to Background Traffic Conditions .............................................................................. 13 Required Due to Total Traffic Conditions ......................................................................................... 13 Combined Entrance ................................................................................................................................ 14 CONCLUSIONS......................................................................................................................................... 14 Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page ii List of Figures Figure 1 - Project Location ........................................................................................................................... 2 Figure 2 - Preliminary Site Plan .................................................................................................................... 3 Figure 3 - Existing AM Peak Hour Conditions ............................................................................................. 5 Figure 4 - Existing PM Peak Hour Conditions ............................................................................................. 5 Figure 5 - Build Out Year AM Peak Hour Background Traffic ................................................................... 7 Figure 6 - Build Out Year PM Peak Hour Background Traffic .................................................................... 7 Figure 7 - Trip Distribution ........................................................................................................................... 8 Figure 8 - AM Peak Hour Site Traffic ......................................................................................................... 9 Figure 9 - PM Peak Hour Site Traffic ........................................................................................................... 9 Figure 10 - Build Out Year Total AM Peak Hour Traffic .......................................................................... 10 Figure 11 - Build Out Year Total PM Peak Hour Traffic ........................................................................... 10 Figure 12 - Trip Generatation of Office Development ............................................................................... 13 List of Tables Table 1 – Accident Data for Goddard Creek Way and McMillan Road 2011-2015..................................... 6 Table 2 - Intersection Traffic Data ................................................................................................................ 6 Table 3 - Trip Generation ............................................................................................................................. 8 Table 4 - AM Peak Hour Intersection Analysis Summary ......................................................................... 11 Table 5 - PM Peak Hour Intersection Analysis Summary .......................................................................... 11 Table 6 - Roadway Segment Analysis ........................................................................................................ 12 Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho Page 1 EXECUTIVE SUMMARY Introduction Thompson Engineers, Inc. has been retained to prepare a traffic impact study for the proposed Goddard Creek Subdivision in Meridian, Idaho. The project is located near the intersection of McMillan Road and Goddard Creek Road, approximately as shown in Figure 1 in the main body of this report. This report has been prepared in conformance with the recommended practices of the Institute of Transportation Engineers. Proposed Development The project is a mixed use development of approximately 74 units of four plex and 6.01 acres of self storage. The preliminary plat was not finalized at the time of this report. The four plexes are expected to access the transportation system through Goddard Creek Way via Apgar Creek Lane. Apgar Creek Lane is a private lane. The storage units will access McMillan Road directly. The site is within the Meridian City Limits. Study Area The area of influence is anticipated to be Ada County, Idaho, including the City of Meridian. The primary impacts will be along McMillan Road and Goddard Creek Way. The study area will include the intersections of McMillan Road and Goddard Creek Way and Goddard Creek Way and Apgar Creek Lane. Conclusions Below are the findings of this report: Based on the trip generation methods recommended in the Trip Generation Manual, the site will generate 705 trips per day, of which 54 trips will occur during the AM peak hour and 68 trips will occur during the PM peak hour. The four plexes will generate 492 of the daily trips, 38 of the AM peak hour trips, and 46 of the PM peak hour trips. If the site is developed as office space, the site is estimated to generate 1340 daily trips, 207 AM peak hour trips, and 200 PM peak hour trips. The project will impact the intersections of McMillan Road and Goddard Creek Way, and Goddard Creek Way and Apgar Creek Lane. The intersection of McMillan Road and Goddard Creek Way is anticipated to operate at LOS C under total traffic conditions in the build out year. The critical peak hour is in the PM peak hour. The intersection of Goddard Creek Way and Apgar Creek Lane is anticipated to operate at LOS B under total traffic conditions in the build out year. The critical peak hour is in the PM peak hour. Goddard Creek Way is anticipated to operate below the maximum recommended volume for LOS D under total traffic conditions. Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 2 INTRODUCTION Thompson Engineers, Inc. has been retained to prepare a traffic impact study for the proposed Goddard Creek Subdivision in Meridian, Idaho. The project is located near the intersection of McMillan Road and Goddard Creek Road, approximately as shown in Figure 1. The purpose of this study is to evaluate the potential traffic impacts resulting from the project and make recommendations for mitigation of those impacts. In particular, the scope of the study includes the following: Trip generation of the proposed development Trip distribution and traffic assignment of the site generated traffic The capacity of the transportation system to support the development Intersection treatment of the site access points Figure 1 - Project Location Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 3 PROPOSED DEVELOPMENT The project is a mixed use development of approximately 74 four plex units and 6.01 acres of self storage. The preliminary plat was not finalized at the time of this report. A preliminary site plan is shown in Figure 2. The four plexes are expected to access the transportation system through Goddard Creek Way via Apgar Creek Lane. Apgar Creek Lane is a private lane. The storage units will access McMillan Road directly. Figure 2 - Preliminary Site Plan STUDY AREA CONDITIONS Study Area The area of influence is anticipated to be Ada County, Idaho, including the City of Meridian. The primary impacts will be along McMillan Road. The study area will include the intersection of McMillan Road and Goddard Creek Way. Land Use The site is within the Meridian City limit and is currently vacant. Existing zoning is for commercial use. Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 4 STUDY PERIOD Build Out Year The Build out Year for this project is assumed to be 2022 which will allow for full occupancy. Actual build out of the site will depend on market conditions and project implementation. Time Period AM and PM peak hour conditions will be studied, in accordance with the requirements of the Ada County Highway District. EXISTING CONDITIONS Road System McMillan Road is classified as a principal arterial roadway in the vicinity of this project. In front of the project, there is one lane in each direction. East and west of the project, there is a center left turn lane, including at the intersection with Goddard Creek. In front of the project there is no curb gutter or sidewalk. There is a posted speed limit of 40 MPH in front of the project. Goddard Creek Way is unclassified by ACHD but functions as a collector road. In the vicinity of this project, it has one through lane in each direction, bike lanes, and curb and gutter on either side of the roadway. There is a posted speed of 20 MPH in front of the project. System Improvements In the ACHD 20 year plan, ACHD has plans to widen McMillan Road to three lanes in the 2031-2035 planning period. In the vicinity of this project, much of McMillan Road is already widened to three lanes. Traffic Volumes AM (7:00 t0 9:00 AM) and PM (4:00 to 6:00 PM) peak hour traffic counts were obtained at the intersection of Goddard Creek Way and McMillan Road and Goddard Creek Way and Apgar Creek Lane the week of May 2, 2017. Existing AM Peak Hour traffic volumes are shown in Figure 3. Existing PM Peak Hour traffic volumes are shown in Figure 4. Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 5 Figure 3 - Existing AM Peak Hour Conditions Figure 4 - Existing PM Peak Hour Conditions Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 6 Accident Analysis Accident data for the intersection of McMillan Road and Goddard Creek Way for the years 2011 through 2015 was obtained from the LHATC. The full report is included in the appendix of this report. Table 1 – Accident Data for Goddard Creek Way and McMillan Road 2011-2015 Fatal Accidents 0 Injury Accidents 0 Property Damage Accidents 3 Total Accidents 3 Contributing factors included failure to yield and speeding. No roadway conditions or visual obstructions were described as contributing factors. Daily traffic was obtained from the COMPASS website from 2014. The average daily traffic was multiplied by 365 to get the annual traffic, multiplied by five to get a five year total, and divided by 1,000,000 to determine the number of million vehicles entering the intersection. Table 2 - Intersection Traffic Data Roadway Direction ADT Goddard Creek Way NB 1847 McMillan Road WB 6058 Daily Vehicles Entering 7905 Million vehicles entering per year (MVE) 2.88 Five Year MVE 14.4 With 3 accidents in a five year period, this will average 0.208 accidents per MVE. This intersection is a multi lane intersection and an undivided road without access control. This type of roadway is defined as a Type 9 roadway in the ITD Safety Evaluation Manual. The average accident rate for this type of intersection in an urban setting is 0.53 accidents per million vehicles entering. This accident rate is below the statewide average. There is no indication of safety problems at this intersection. PROJECTED TRAFFIC Background Traffic Future traffic is obtained by expanding the existing traffic volumes by a growth factor. A growth factor of 2.0% per year is used. The growth factor is applied to the intersection of McMillan and Goddard Creek. The area around Apgar Creek and Goddard Creek is built out so the traffic will not increase due to organic growth. Background AM Peak Hour traffic for the build out year is shown in Figure 5. Background PM Peak Hour traffic for the build out year is shown in Figure 6. Off Site Traffic No other major projects are under construction or in the approval process in the vicinity of this project. Other developments are included in the growth factor. Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 7 Figure 5 - Build Out Year AM Peak Hour Background Traffic Figure 6 - Build Out Year PM Peak Hour Background Traffic Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 8 Trip Generation Site trip generation is estimated using the procedures recommended in the latest edition of the Trip Generation Manual (9th edition), published by the Institute of Transportation Engineers. The land use in the trip generation manual that most closely resembles four plexes is apartments. Site trip generation is obtained by applying the average trip generation rates obtained from the Manual for each category of land use within the development. Table 3 shows the trip generation of the site. Table 3 - Trip Generation Trip Distribution In order to determine impacts, the trips generated by the site must be distributed to destinations throughout Ada County and assigned to the transportation system. The distribution for this development is based on information obtained from COMPASS. It is unlikely that any significant volume of traffic will travel east on Apgar Creek Lane. Site traffic distribution for the development is shown in Figure 7. Figure 7 - Trip Distribution Average Weekday Driveway Volumes Rate Total Rate Num Rate Num 151 Mini Warehouse 6.01 Acres 35.43 213 0%0 0%0 220 Apartment 74 DU 6.65 492 0%0 0%0 Total Average Weekday AM Peak Hour Driveway Volumes Enter Exit Rate Total Rate Num Rate Num Total Rate Total Rate Num Rate Num Total Total 151 Mini Warehouse 6.01 Acres 1.16 7 0%0 0%0 7 1.42 9 0%0 0%0 9 16 220 Apartment 74 DU 0.10 8 0%0 0%0 8 0.41 30 0%0 0%0 30 38 Total 15 0 15 39 0 39 54 Average Weekday PM Peak Hour Driveway Volumes Enter Exit Rate Total Rate Num Rate Num Total Rate Total Rate Num Rate Num Total Total 220 Mini Warehouse 6.01 Acres 1.79 11 0%0 0%0 11 1.79 11 0%0 0%0 11 22 220 Apartment 74 DU 0.40 30 0%0 0%0 30 0.22 16 0%0 0%0 16 46 Total 41 0 41 27 0 27 68 Pass ByITE Code Land Use No.Units 24 hr 2-Way Capture Total 213 492 705 705 ITE Code Land Use No.Units Enter Pass By Capture Exit Pass By Capture Pass By Capture ITE Code Land Use No.Units Enter Pass By Capture Exit Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 9 Site Traffic Site traffic is distributed at the study intersection in accordance with the distribution from Figure 7. Figure 8 shows the distribution of site generated traffic for AM peak hour traffic conditions. Figure 9 shows the distribution of site generated traffic for PM peak hour conditions. Figure 8 - AM Peak Hour Site Traffic Figure 9 - PM Peak Hour Site Traffic Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 10 Total Traffic The site traffic is then added to the background traffic as determined above. Figure 10 shows the total traffic at each intersection for AM peak hour conditions. Figure 11 shows the total traffic at each intersection for PM peak hour traffic conditions f or the build out year of 2022. Figure 10 - Build Out Year Total AM Peak Hour Traffic Figure 11 - Build Out Year Total PM Peak Hour Traffic Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 11 TRAFFIC ANALYSIS Capacity Analysis and Level of Service Capacity analysis was performed using the Highway Capacity Software (HCS2010), based on the 2010 edition of the Highway Capacity Manual. Level of service for stop controlled intersections is based on the average delay of vehicles traveling through the intersection. Table 4 shows the AM peak hour intersection. Table 5 shows the PM peak intersection. Copies of the calculations are included in the appendix of this report. Table 4 - AM Peak Hour Intersection Analysis Summary Table 5 - PM Peak Hour Intersection Analysis Summary Intersection Analysis The intersection of Goddard Creek Way and McMillan Road will operate at LOS C in the PM peak hour under build out traffic conditions. All approaches will operate at LOS D or better. LOS Summary AM Peak Hour Conditions Delay s/v LOS Delay s/v LOS Delay s/v LOS McMillan and Goddard Creek 13.2 B 14.1 B 14.7 B EB Critical Movement 8.2 A 8.4 A 8.4 A SB Critical Movement 15.0 B 16.3 C 17 C Goddard Creek and Apgar 9.7 A 9.7 A 9.9 A EB Critical Movement 9.7 A 9.7 A 9.9 A WB Critical Movement 9.3 A 9.3 A 9.5 A NB Critical Movement 7.6 A 7.6 A 7.5 A SB Critical Movement 7.3 A 7.3 A 7.3 A Storage Entrance 12.8 B Combined Entrance 16.4 C 2017 2022 Existing Background Total LOS Summary PM Peak Hour Conditions Delay s/v LOS Delay s/v LOS Delay s/v LOS McMillan and Goddard Creek 18.2 C 21.6 C 22.6 C EB Critical Movement 10.1 B 10.6 B 10.9 B SB Critical Movement 20.6 C 25.2 D 26.8 D Goddard Creek and Apgar 11.7 B 11.7 B 12.8 B EB Critical Movement 9.4 A 9.4 A 9.6 A WB Critical Movement 11.7 B 11.7 B 12.8 B NB Critical Movement 7.5 A 7.5 A 7.6 A SB Critical Movement 7.6 A 7.6 A 7.3 A Storage Entrance 9.6 A Combined Entrance 17.3 C 2017 2022 Existing Background Total Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 12 The intersection of Apgar Way and Goddard Creek Way is anticipated to operate at LOS B in the PM peak hour under both existing and build out conditions. The eastbound approach will operate at LOS A The entrance to the storage facility will operate at LOS B in the AM peak hour. As an alternative to taking access on Apgar Way, all site traffic could access the transportation system directly on to McMillan Road via a combined access. If all site traffic is added to one intersection, the combined intersection will operate at LOS C in the PM peak hour and LOS B in the AM peak hour. Roadway Analysis Roadway segments are analyzed under horizon year peak hour traffic in accordance with Table 2 of the ACHD Development Policy Manual. The results are shown in Table 6. Table 6 - Roadway Segment Analysis Roadway Segment Location Direction Peak Hour Build Out Year Traffic Site Traffic Off Site Traffic Total Traffic McMillan W. of Goddard Creek EB AM 521 7 0 528 WB PM 764 20 0 784 Goddard Creek Way N. of McMillan NB PM 205 30 0 235 SB AM 196 24 0 220 McMillan Road functions as a primary arterial road and should be limited to LOS E with a maximum of 880 vehicles per hour in the peak direction. When the road is fully widened to three lanes, it should operate below the LOS E threshold. Goddard Creek functions as a collector road and should be limited to LOS D with a maximum of 425 vehicles per hour in the peak direction. At build out, Goddard Creek will operate will below the maximum recommended volume. Site Access The developer is proposing accesses via Goddard Creek Way for the apartments, and to McMillan Road for the self storage facility. The development has a cross access agreement to use the private road. All approaches will be public approach and will exceed the recommended spacing requirements in the ACHD Development Policy Manual. There is no proposed direct access on to Goddard Creek Way by individual lots. DISCUSSIONS Approved Land Use The site has been approved for commercial land uses under a previously approved development application. Typically, such a land use would be for office uses, but could include coffee shops, hair salons or other retail uses. A site plan for any of these uses has not been developed at this time, however the intensity of the land use can be estimated Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 13 using a Floor Area Ratio (FAR) of 22%. This means that only 22% of the total area of the site could be developed as floor space. The remaining 78% of the area would be dedicated for parking and access, landscaping, storm drainage, and setbacks. For a 12 acre site, a 22% FAR would allow 115,000 SF of office space. Traffic from such a development can be estimated using the same trip generation techniques as done for the proposed site. Trip generation for an office development is shown in Table 12. Figure 12 - Trip Generatation of Office Development Roadway Improvements Required Due to Existing Traffic Conditions The intersection of Goddard Creek Way and McMillan Road functions at an acceptable level of service under existing traffic conditions. No improvements are required. The intersection of Goddard Creek Way and Apgar Creek Lane functions at an acceptable level of service under existing conditions. No improvements are required. Goddard Creek Way is operating below capacity under existing conditions. Required Due to Background Traffic Conditions The intersection of Goddard Creek Way and McMillan Road is anticipated to function at an acceptable level of service under background traffic conditions. No improvements are required. The intersection of Goddard Creek Way and Apgar Creek Lane is anticipated to function at an acceptable level of service under background conditions. No improvements are required. Goddard Creek Way is anticipated to operate below capacity under background traffic conditions. Required Due to Total Traffic Conditions The intersection of Goddard Creek Way and McMillan Road is anticipated to function at an acceptable level of service under total traffic conditions. No improvements are required. Average Weekday Driveway Volumes Rate Total Rate Num Rate Num 715 General Office 115 TSF 11.65 1340 0%0 0%0 Average Weekday AM Peak Hour Driveway Volumes Enter Exit Rate Total Rate Num Rate Num Total Rate Total Rate Num Rate Num Total Total 715 General Office 115 TSF 1.60 184 0%0 0%0 184 0.20 23 0%0 0%0 23 207 Average Weekday PM Peak Hour Driveway Volumes Enter Exit Rate Total Rate Num Rate Num Total Rate Total Rate Num Rate Num Total Total 715 General Office 115 TSF 0.26 30 0%0 0%0 30 1.48 170 0%0 0%0 170 200 Capture Total 1340 ITE Code Land Use No.Units Enter Pass ByITE Code Land Use No.Units 24 hr 2-Way Capture Exit Pass By Capture ITE Code Land Use No.Units Enter Pass ByPass By Capture Pass By Capture Exit Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 14 The intersection of Goddard Creek Way and Apgar Creek Lane is anticipated to function at an acceptable level of service under total conditions. No improvements are required. Goddard Creek Way is anticipated to operate below capacity under total traffic conditions. Combined Entrance If it is decided to provide access for both land uses through a single entrance on McMillan Road, it will operate at an acceptable level of service under total traffic conditions. CONCLUSIONS This study identifies transportation impacts associated with the proposed Goddard Creek subdivision in Meridian, Idaho. The project is a high density residential and self storage facility development. Below are the findings of this report: This project is a proposed residential development of 74 four plexes and 6.01 acres of self storage. The residential portion of the development will access Goddard Creek Way via Apgar Creek Lane. The self storage facility will access McMillan Road directly. Based on the trip generation methods recommended in the Trip Generation Manual, the site will generate 705 trips per day, of which 54 trips will occur during the AM peak hour and 68 trips will occur during the PM peak hour. The four plexes will generate 492 of the daily trips, 38 of the AM peak hour trips, and 46 of the PM peak hour trips. If the site is developed as office space, the site is estimated to generate 1340 daily trips, 207 AM peak hour trips, and 200 PM peak hour trips. The project will impact the intersections of McMillan Road and Goddard Creek Way, and Goddard Creek Way and Apgar Creek Lane. The intersection of McMillan Road and Goddard Creek Way is anticipated to operate at LOS C under total traffic conditions in the build out year. The critical peak hour is in the PM peak hour. The intersection of Goddard Creek Way and Apgar Creek Lane is anticipated to operate at LOS B under total traffic conditions in the build out year. The critical peak hour is in the PM peak hour. Goddard Creek Way is anticipated to operate below the maximum recommended volume for LOS D under total traffic conditions. Traffic Impact Study Goddard Creek Subdivision, Meridian, Idaho C:\Users\dan\Documents\TEI\projects\17-09 Goddard Creek\docs\Goddard Creek TIS.docx Page 15 APPENDIX Traffic Counts Accident Data AM HCS Calculations PM HCS Calculation