TIS Executive Summary

City of Glendale — Regular Meeting (2024-09-24)

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TRAFFIC IMPACT STUDY 
Westgate Multifamily 
SWC of 99th Avenue and Myrtle Avenue 
Glendale, Arizona 
 
 
 
 
September 13, 2023 
Revision #1: March 8, 2024 
Revision #2: May 9, 2024 
 
 
 
 
 
 
 
 
 
 
PREPARED FOR 
Mattson Construction 
175 South Hamilton Place 
Building 7, Suite 115 
Gilbert, AZ 85233 
 
 
 
PREPARED BY 
 
Alan Heathcoat P.E.
Principal Engineer
Glendale Transportation
05/22/2024 9:57:14 AM
APPROVED

INTELLIGENT TRANSPORTATION     ●     TRAFFIC     ●     TRANSPORTATION PLANNING     ●     TRAFFIC DATA COLLECTION 
 
TRAFFIC IMPACT STUDY 
Westgate Multifamily 
SWC of 99th Avenue and Myrtle Avenue 
Glendale, Arizona 
 
 
 
September 13, 2023 
Revision #1: March 8, 2024 
Revision #2: May 9, 2024 
 
 
 
 
PREPARED FOR 
Mattson Construction 
175 South Hamilton Place 
Building 7, Suite 115 
Gilbert, AZ 85233 
 
 
PREPARED BY 
 
2803 N. 7th Avenue 
Phoenix, Arizona 85007 
 
 
   
UCG Project Number:  TR23105 
 
 
 
 
 
 
 
 
 
 
 
 
 
Conducted by: 
Sarah Simpson PhD, PE 
 
President

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TABLE OF CONTENTS 
I. EXECUTIVE SUMMARY .................................................................................................................................. 1 
A. STUDY GUIDELINES ................................................................................................................................................. 1 
B.  STUDY OBJECTIVES ................................................................................................................................................ 2 
C.  FINDINGS AND RECOMMENDATIONS ......................................................................................................................... 2 
II. PROPOSED DEVELOPMENT .......................................................................................................................... 4 
A.  SITE LOCATION ..................................................................................................................................................... 4 
B.  LAND USE ............................................................................................................................................................ 4 
C.  PHASING AND TIMING ............................................................................................................................................ 4 
D.  SITE ACCESSIBILITY ................................................................................................................................................ 5 
III. STUDY AREA CONDITIONS ........................................................................................................................... 9 
A.  STUDY AREA ......................................................................................................................................................... 9 
B.  STUDY AREA LAND USE .......................................................................................................................................... 9 
C.  ANTICIPATED FUTURE DEVELOPMENT AND PLANNED IMPROVEMENTS ............................................................................. 9 
C.1. City of Glendale Capital Improvement Projects ......................................................................................... 9 
C.2. City of Glendale Development in the Vicinity of the Site ......................................................................... 10 
IV. LEVEL OF SERVICE METHODOLOGY ........................................................................................................... 11 
V. EXISTING ROADWAY CONDITIONS ............................................................................................................. 13 
A.  PHYSICAL CHARACTERISTICS ................................................................................................................................... 13 
B.  EXISTING TRAFFIC VOLUMES .................................................................................................................................. 14 
C.  EXISTING TRAFFIC OBSERVATIONS ........................................................................................................................... 14 
D.  CRASH DATA ...................................................................................................................................................... 17 
E. EXISTING INTERSECTION LEVEL OF SERVICE ANALYSES .................................................................................................. 19 
VI. BACKGROUND TRAFFIC ............................................................................................................................. 20 
VII. PROJECTED TRAFFIC ................................................................................................................................. 27 
A.  TRIP GENERATION ............................................................................................................................................... 27 
B.  TRIP DISTRIBUTION .............................................................................................................................................. 28 
C.  PROJECTED TOTAL TRAFFIC VOLUMES ..................................................................................................................... 31 
VIII. TRAFFIC AND IMPROVEMENT ANALYSIS ................................................................................................. 35 
A. ROADWAY IMPROVEMENTS .................................................................................................................................... 35 
B.  SITE ACCESSIBILITY ............................................................................................................................................... 35 
C.  TURN LANE ANALYSIS ........................................................................................................................................... 38 
C.1. Right-Turn Deceleration Lanes ................................................................................................................ 38 
C.2. Left-Turn Deceleration Lanes ................................................................................................................... 38 
D. TRAFFIC SIGNAL WARRANT ANALYSIS ...................................................................................................................... 38 
E.  INTERSECTION LEVEL OF SERVICE ANALYSES FOR TOTAL TRAFFIC CONDITIONS ................................................................. 40 
F. COMMERCIAL AND INDUSTRIAL DRIVEWAYS/THROAT LENGTH ...................................................................................... 44 
G.  INTERSECTION SIGHT DISTANCE.............................................................................................................................. 44 
IX. CONCLUSIONS AND RECOMMENDATIONS................................................................................................. 45 
X. LIMITATIONS ............................................................................................................................................. 47 
XI. SOURCES .................................................................................................................................................. 48

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LIST OF TABLES 
TABLE 1:  INTERSECTION LEVELS OF SERVICE AND DELAY ....................................................................................... 11 
TABLE 2:  INJURY SEVERITY 2020-2022 .................................................................................................................... 17 
TABLE 3:  COLLISION MANNER 2020-2022 .............................................................................................................. 18 
TABLE 4:  EXISTING CONDITIONS INTERSECTION LEVELS OF SERVICE ..................................................................... 19 
TABLE 5:  2026 BACKGROUND INTERSECTION LEVELS OF SERVICE ......................................................................... 21 
TABLE 6:  2029 BACKGROUND TRAFFIC INTERSECTION LEVELS OF SERVICE ........................................................... 22 
TABLE 7:  2039 BACKGROUND TRAFFIC INTERSECTION LEVELS OF SERVICE ........................................................... 23 
TABLE 8:  TRIP GENERATION .................................................................................................................................... 27 
TABLE 9:  TRIP DISTRIBUTION PERCENTAGES .......................................................................................................... 28 
TABLE 10:  2026 TOTAL TRAFFIC INTERSECTION LEVELS OF SERVICE ...................................................................... 41 
TABLE 11:  2029 TOTAL TRAFFIC INTERSECTION LEVELS OF SERVICE ...................................................................... 42 
TABLE 12:  2039 TOTAL TRAFFIC INTERSECTION LEVELS OF SERVICE ...................................................................... 43 
 
LIST OF FIGURES 
FIGURE 1:  VICINITY MAP ........................................................................................................................................... 6 
FIGURE 2:  AERIAL VIEW ............................................................................................................................................. 7 
FIGURE 3: MULTIFAMILY DEVELOPMENT SITE PLAN ................................................................................................. 8 
FIGURE 4: EXISTING CONDITIONS ............................................................................................................................ 15 
FIGURE 5: EXISTING TRAFFIC COUNTS ..................................................................................................................... 16 
FIGURE 6: BACKGROUND TRAFFIC – YEAR 2026 ...................................................................................................... 24 
FIGURE 7: BACKGROUND TRAFFIC – YEAR 2029 ...................................................................................................... 25 
FIGURE 8: BACKGROUND TRAFFIC - YEAR 2039 ....................................................................................................... 26 
FIGURE 9: SITE GENERATED TRAFFIC AND TRIP DISTRIBUTION – PHASE I............................................................... 29 
FIGURE 10: SITE GENERATED TRAFFIC AND TRIP DISTRIBUTION – FULL BUILTOUT ................................................ 30 
FIGURE 11: TOTAL TRAFFIC - YEAR 2026 .................................................................................................................. 32 
FIGURE 12: TOTAL TRAFFIC - YEAR 2029 .................................................................................................................. 33 
FIGURE 13: TOTAL TRAFFIC - YEAR 2039 .................................................................................................................. 34 
FIGURE 14: DRIVEWAY SPACING .............................................................................................................................. 37 
 
Appendix A . . . Traffic Data 
Appendix B . . . Capacity Analyses 
Appendix C . . . Signal Warrant Analysis 
 
Appendix D . . . Comments and Responses

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I. EXECUTIVE SUMMARY 
Mattson Construction retained United Civil Group (UCG) to perform this Traffic 
Impact Study (TIS) for the planned Westgate Multifamily Development located on the 
southwest corner of 99th Avenue and Myrtle Avenue in Glendale, Arizona.   The site is   
approximately 19 acres of vacant land, Maricopa County Assessor’s parcels (142-57-
022, 142-57-022A, 142-57-003Z, 142-57-003H, 142-57-002D, a portion of 142-57-
003U, and a portion of 142-57-002F). The site will be developed as (4) four-story 
buildings with a total of 457 multifamily units. In addition, 13,000 square feet of retail 
development is proposed on the east side of the site. 
 
It is assumed that this development will be constructed in two phases. Phase I will 
consist of 239 units constructed and occupied by 2026. Phase II consists of the 
remaining 218 units plus the retail which will be constructed and occupied by the year 
2029.   
 
Three new site accesses and one existing access are proposed for this development. 
Two new site accesses are planned for Phase I of the development.   The main access 
for Phase I (Access A) is planned on Myrtle Avenue with secondary exit only access 
(Access B) on 99th Avenue.  For Phase II of the development, the site will obtain 
access from the existing middle driveway on Glendale Avenue (Access C) with 
secondary exit only access (Access B) on 99th Avenue. A new access is proposed for 
the retail development (Access D) that will align with the existing bus-only driveway 
for the park and ride on the east side of 99th Avenue. 
 
A. Study Guidelines 
 
This TIS has been performed in general conformance with the City of Glendale’s 
Guide for the Submittal of Traffic Statements and Traffic Impact Analysis dated March 
2023, and per scoping information provided by City of Glendale Transportation 
Department, locally accepted standards, and industry practice.  Per the City’s Guide, 
this planned multifamily residential development is characterized as an Analysis 
Category I, small development which generates 100 or more peak hour trips but 
fewer than 499 peak hour trips.  As such, the study horizon years for this development 
are the opening year 2026, and the full build out year 2029 plus 10 years after 
opening, year 2039.  The minimum study area is defined as all site access driveways 
and all signal-controlled intersections within 1 mile of either side if the development. 
 
Within these parameters and based on discussions with the City of Glendale, the 
intersections of 99th Avenue/Cardinals Way, 99th Avenue/Glendale Avenue, 99th 
Avenue/Hospital Driveway, 99th Avenue/Maryland Avenue, 99th Avenue/Myrtle 
Avenue alignment, Glendale Avenue/West Access, Glendale Avenue/Middle Access,

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Glendale Avenue/East Access, and SR 101L/Glendale Avenue are included in the 
study area.    
B.  Study Objectives 
This study is intended to investigate the existing and future traffic conditions and 
identify any potential roadway improvements necessary to serve the proposed 
development.  Major study objectives of this traffic report are as follows: 
 
• Analyze the existing study area intersections and site accessibility for the 
development. 
 
• Determine the site traffic volumes generated by the proposed development 
and their impacts on the surrounding study area and roadway network. 
 
• Where applicable, recommend safety, intersection and/or roadway 
improvements, sufficient to meet the needs of the development and adjacent 
roadway network due to the additional site generated traffic volumes. 
C.  Findings and Recommendations 
Based on the analyses within this TIA, the following findings are presented. 
 
The forecasted trip generation for a multifamily 457-unit development plus 13,000 
square feet of retail development was calculated based on values presented within 
the ITE Trip Generation Manual, 11th Edition.  On a weekday, after full build-out of the 
site, it is anticipated that the overall development will generate a total of 2,856 daily 
trips with 206 trips occurring in the morning peak hour and 273 trips occurring in the 
evening peak hour. 
 
Crash history was assessed for a 3-year period, year 2020 through 2022 at the study 
area intersections of 99th Avenue/Maryland Avenue, 99th Avenue/Glendale Avenue 
and 99th Avenue/Cardinals Way. At the reviewed study area intersections, a total of 74 
reportable crashes occurred.  Of the 74 reportable crashes, 47 were noted as no 
injury, 17 were noted as possible injury, 8 were noted as suspected minor injury, one 
was suspected serious injury, and one was fatal.  The collision manner with the 
highest type of crash was Angle (19), followed by Rear End (16) and Left Turn (15). 
 
A right turn deceleration lane is warranted and recommended on the major arterial 
roadway, 99th Avenue, for southbound traffic at Access D.  
 
Based on traffic signal warrants, a traffic signal is not warranted at the middle site 
access/Glendale Road through the study horizon. The signal warrant was based on 
forecasted traffic volumes generated by increasing the existing traffic counts and 
including other known developments plus the trips that will be generated by this 
proposed multifamily and retail development.

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Through the study horizon 2039, the study area intersections operate at acceptable 
LOS D or better except for the existing driveways on Glendale Avenue. Similar to the 
background conditions, the southbound left turn movements operate with some 
delay through the horizon year. For the unsignalized intersections, stop-control on the 
minor roads and driveways that intersect with major streets typically experience 
greater delay for short periods of time in the peak hours due to the wait time 
experienced for acceptable gaps on the major street, while the free-flowing major 
streets experience minimal to no delay. In addition, signals on Glendale Avenue 
within close proximity to the site will provide additional gaps in traffic that are not 
accounted for in the modeling software. These gaps will assist in allowing motorists to 
exit the site during the peak periods. 
   
Proper intersection sight distance and sight triangles shall be provided and 
maintained at the site accesses and intersections of the proposed development to 
give drivers exiting the accesses a clear view of oncoming traffic.  The landscape and 
hardscape within the sight triangles must not obstruct the driver’s view of the 
adjacent travel lanes.  To ensure adequate sight distances and sight distance 
triangles, AASHTO’s A Policy on Geometric Design of Highways and Streets Section 
9.5 should be followed as appropriate when designing the accesses and landscaping.  
 
Based on the findings of this TIA, the following recommendations apply: 
 
• 99th Avenue - Reserve 65 feet of right of way measured centerline to right of way 
line along the site’s eastern boundary. Construct half street improvements per 
City of Glendale Detail G-303 Major Arterial Section A-4. 
 
• Myrtle Avenue – Reserve 35 feet of right of way measured centerline to right of 
way line along the site’s northern boundary. Construct half street improvements 
per City of Glendale Detail G-304 Collector Section C-1. 
 
• Right Turn Lane – Install right turn lane for southbound traffic on 99th Avenue at 
Access D. The right turn lane at Access D should be designed with a minimum of 
150 feet of storage with a 150’ radius S-curve taper, approximately 84 feet. 
 
• Access B – Design Access B as a right out only driveway. Limit right in 
movements by the design of the driveway access.