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Item 8 & 9 - TIAKelly & Associates 785 Sleepy Creek Drive, Frisco, Texas, 75034 (214) 697-1328 (972) 668-7867 fax TECHNICAL MEMORANDUM To: Justin L. Lansdowne, P.E. G & A Consultants, LLC From: Rod Kelly, P.E. Kelly & Associates Date: September 5, 2017 RE: Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas PURPOSE The purpose of this revised memorandum is to document the results of a traffic impact analysis (TIA) for the proposed medical-dental/general office development, to be located at the southwest corner of N. Kimball Avenue and E. Highland Street in Southlake, Texas (See Figure 1). The proposed development site plan is shown in Figure 2. The revised TIA report was prepared in response to comments from the City of Southlake, concerning the initial TIA, which was conducted to determine the possible impacts of the proposed development on traffic operations along North Kimball Avenue, adjacent to this development. The TIA also examined the development driveways to determine compliance with City ordinance requirements related to location, spacing, sight distance, internal site vehicle storage / throat length, and the need for right and/or left turn lanes on the adjacent street. Figure 1 – Site Vicinity Map Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 2 of 44 September 5, 2017 Figure 2 – Site Plan ANALYSIS APPROACH  New traffic counts were obtained to establish existing traffic volumes at the development access driveway intersections and East Highland Street with North Kimball Avenue. The counts were obtained for the morning and afternoon peak traffic conditions. PM peak period traffic counts were conducted on Tuesday, June 27, 2017 , and the AM peak period counts were conducted on Thursday, August 31, 2017, to include the nearby middle school tra ffic. These traffic counts are provided in Appendix A. The AM and PM peak hour existing traffic data was balanced to eliminate minor traffic volume continuity differences and is summarized in Figure 3 and Figure 4. Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 3 of 44 September 5, 2017 Figure 4 – Existing AM Peak Hour Non-Site Traffic Figure 4 – Existing PM Peak Hour Non-Site Traffic Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 4 of 44 September 5, 2017 Vehicle trips in and out of proposed development were determined for the AM and PM peak hour of traffic. Using the 9th Edition of the ITE Trip Generation Manual information provided in Appendix B, the weekday AM and PM peak hour trip generation rates were calculated. The resulting rates and proposed development vehicle trip calculations are shown in Table 1. Table 1 – Development Trip Generation Calculations  Vehicle trips in and out of proposed development were determined for the AM and PM peak hour of traffic and are shown in Table 2. Table 2 – Development Trip Generation Use ITE Code Unit of Measure AM Peak Hour PM Peak Hour In Out In Out Medical- Dental Ofc. 720 25,000 S.F. 47 13 24 60 General Office 710 19,256 S.F. 45 6 17 83 All Land Uses 44,256 S.F. 92 19 41 143  The directions of approach and departure for traffic entering and exiting the proposed development were determined. The directions of approach and departure were derived from a combination of (1) viewing the existing housing development density contained on an aerial map of the area within 3 miles of the site, (2) determining the directions of approach and departure at the SH 114/N Kimball Ave interchange, and (3) considering the distribution of the trips at the intersections counted for the subject TIA. This combined information indicated that the general approach/departure patterns developed for the subject site would be approximately as follows: PM Peak Hour General Approach and Departure Patterns - 20% from and to the North - 25% from and to the South - 10% from and to the East - 45% from and to the West The major traffic arteries that would be primarily used to access the site are shown in Figure 5. It should also be noted that Grapevine Lake limits access to the north of the site. For the traffic impact analysis, it was decided to use the existing non -site volumes and let the results of the capacity analyses determine whether additional traffic proj ections and analysis would be necessary. Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 5 of 42 September 5, 2017 Figure 5 – Major Site Access Roadways  Trips generated by the proposed development were then assigned to the appropriate approaches of the intersections to be analyzed. These volumes are shown in Figure 6 and Figure 7.  The existing non-site traffic volumes and that which will be generated by the proposed development at the intersection of N Kimball Ave and E Highland St, as well as the intersections of N Kimball Ave with the development driveways 1 and 2, wer e combined. These volumes are shown in Figure 8 and Figure 9. Figure 6 – AM Peak Hour Site Traffic Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 6 of 42 September 5, 2017 Figure 7 – PM Peak Hour Site Traffic Figure 8 – Combined AM Peak Hour Site + Non-Site Traffic Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 7 of 42 September 5, 2017 Figure 9 – Combined PM Peak Hour Site + Non-Site Traffic  The 2017 traffic lane configurations and intersection traffic control were also determined and are displayed in Figure 10. Figure 10 - Lane Configurations & Traffic Control Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 8 of 42 September 5, 2017  The above traffic information was entered as input data into Trafficware’s “Synchro” traffic analysis software package, both for the existing traffic conditions and for conditions that included the traffic added by the proposed development. CAPACITY ANALYSIS FINDINGS The analysis of impacts is measured in terms of traffic operating level of service (LOS). According to the Highway Capacity Manual, capacity is defined as the maximum number of vehicles that can be expected to travel on a given section of roadway or a specific lane during a given period under prevailing traffic conditions. The operational conditions of roadways are measured in terms of "Level of Service" (LOS). Level of Service refers to the operational conditions within a traffic stream and their perception by motorists in terms of delay, freedom to maneuver, traffic interruptions, comfort, convenience and safety. There are six levels of service (LOS) or capacity conditions for each roadway facility and they are designated from "A" to "F", with "A" representing an optimal, free -flow condition, and "F" representing a congested, forced flow condition . These Delay/LOS relationships are shown in Table 2 for intersections with stop sign and traffic signal control. Table 2 - Relationship between Delay and LOS Average Vehicle Delay (Seconds) per Vehicle for Stop Controlled Intersections LOS (Vol./Cap. Ratio) < or = to 1 < or = to 10 A >10 & < or = 15 B >15 & < or = 25 C >25 & < or = 35 D >35 & <or = 50 E >50 F For the analysis of the impacts of expected traffic operations in the AM peak hour at the intersection of N. Kimball Ave. and Highland St. and the proposed intersections of Driveway 1 and 2 with N Kimball Ave, the Synchro traffic analyses were conducted. A summary of the AM peak hour analysis results are shown in Table 3. The AM peak hour capacity analysis worksheets for the stop sign controlled intersections are contained in Appendix C. Table 3 – Site + Non-Site AM Peak Hour Analysis Results As can be seen from the delay and LOS results, all analyzed intersections and associated approaches will operate at a high LOS C or better. Because of these highly favorable levels of service and the fact that the area served by the subject roadway segments and intersections is almost fully developed, it is expected that there will be more than adequate traffic capacity on these streets for the foreseeable future; therefore, no additional non -site traffic projections were made. Intersection No Mitigation With Traffic Mitigation Intersection LOS Approach Approach LOS Mitigation Measures Intersection LOS Approach LOS N Kimball Ave & E Highland St A EB C None required NB A SB A Driveway 1 & N Kimball Ave A EB C None required WB C NB A SB A Driveway 2 & N Kimball Ave A EB B None Required WB C NB A SB A Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 9 of 42 September 5, 2017 A summary of the PM peak hour analysis results are shown in Table 4. The PM peak hour capacity analysis worksheets for the stop sign controlled intersections are contained in Appendix C. Table 4 – Site + Non-Site PM Peak Hour Analysis Results Intersection No Mitigation With Traffic Mitigation Intersection LOS Approach Approach LOS Mitigation Measures Intersection LOS Approach LOS N Kimball Ave & E Highland St A EB B None required NB A SB A Driveway 1 & N Kimball Ave A EB B None required WB C NB A SB A Driveway 2 & N Kimball Ave A EB B None Required WB C NB A SB A As can be seen from the delay and LOS results, all analyzed intersections and associated approaches will operate at a high LOS C or better. Because of these highly favorable levels of service and the fact that the area served by the subject roadway segments and intersections is almost fully developed, it is expected that there will be more than adequ ate traffic capacity on these streets for the foreseeable future; therefore, no additional non -site traffic projections were made.  Researched City of Southlake and TxDOT access management standards associated with the need for separate right and left turn deceleration lanes. ACCESS MANAGEMENT STANDARDS ANALYSIS The City of Southlake access management standards are contained in Driveway Ordinance 654, which contain criteria for left and right turn lanes, access drive location and spacing, sight d istances, and of-street internal site driveway storage / throat length that can be applied to this proposed development site. Excerpts from the relevant sections of this document, referenced in the following discussions, are provided in Appendix D. Turn Lane Requirements – N. Kimball Avenue Left Turn Lane Requirements Since median openings and exclusive northbound left turn lanes already exists at the intersections of N. Kimball Ave with the driveways serving the proposed development, there are provisions for queuing of vehicles turning left into the development for northbound N. Kimball Ave. The results of the queuing analysis, as defined in Footnote 5 of Table 3-3: Lengths of Single Left-Turn Lanes on Urban Streets, in the TxDOT Roadway Design Manual, was conducted as a part of the overall Synchro intersection capacity analyses. This reference table is contained in Appendix D. The analysis indicated that the existing northbound left turn lane storage of approximately 70 feet at the two development access driveways, as shown in Table 5, will be adequate to accommodate the 36 northbound vehicles in the AM peak hour and the 15 northbound vehicles in the PM peak hour turning left into each of the two development site driveways. Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 10 of 42 September 5, 2017 Table 5 – Left Turn Lane Vehicle Queuing (Synchro) N Kimball Ave Left Turn Lane @ Peak Hour 95th Percentile Queue Length Driveway 1 AM 4 feet (1 vehicle) Driveway 2 AM 4 feet (1 vehicle) Driveway 1 PM 1 foot (1 vehicle) Driveway 2 PM 1 foot (1vehicle) Right Turn Lane Requirements For right turn lanes, subsection 5.4a of the City’s driveway ordinance shows that a right turn deceleration lane shall be provided for any driveway located on an arterial street if the speed limit is equal to or less than 40 MPH and the right tu rn ingress volume exceeds 50 vehicles in the design hour. Since the Site Driveways 1 and 2 are projected to have no more than 10 vehicles turning right into these driveways in either the AM or PM peak hours (which is below the threshold volume of 50); no separate right turn lanes will be required. TxDOT criteria, contained in Appendix D, indicates that if the speed limit on the roadway is equal to or less than 45 MPH and the volume of right turning vehicles is greater than 60 vehicle per hour, a separate right turn lane will be required. As with the City’s criteria, the volume of right turning traffic into any of the proposed development driveways does not exceed TxDOT threshold criteria. Access Drive Location and Spacing The locations of the development access driveways were established in accordance with Section 5.1 of the City’s driveway ordinance, which defines the standards for placement of driveways on City streets. The driveway locations and spacing, as shown in Site Plan in Figure 2, meet the requirement shown in Table One of this ordinance, as shown in Appendix D, except for the distance between Driveway 2 and Southlake Glen Drive. In this instance, the spacing is only 110 feet , while 200 feet is required. Because it will be desirable to locate the driveway at an existing median opening, a variance should be requested. Driveway Sight Distances Observations made at the development site indicated that there is generally flat terrain and straight roadway alignment, with no obstructions, in both directions adjacent to the subject development, to provide clear and adequate sight distance at the two proposed development access driveways. Internal Storage/ Throat Length Table Two, in Subsection 5.2d of the City’s driveway ordinance, indicates that, based on the number of required parking spaces, 100 feet of internal / throat vehicle storage will be required within the proposed development site. However, the vehicle queuing analysis results from the Synchro analysis indicates that only a maximum queuing storage of 16 feet for 1 vehicle will ever be required for vehicles exiting either of the two access driveways. This information can be found in the Synchro analysis worksheets, in Appendix C. Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 11 of 42 September 5, 2017 CONCLUSIONS Based upon the Analysis Findings discussed above, the following conclusions can be drawn. Intersection Levels of Service – The overall intersection and intersection approach Levels of Service (LOSs) for existing conditions, with development traffic added, were all found to be expected to be at highly acceptable free or stable traffic flow rates. Because of these highly favorable levels of service and the fact that the area served by the subject roadway segments and intersection s is almost fully developed, it is expected that there will be more than adequate traffic capacity on these streets for the foreseeable future and no additional non-site traffic projections are necessary. Turn Lane Requirements - Based on City of Southlake and TxDOT access management standards, no separate southbound right turn lanes on N. Kimball Ave. will be warranted for either of the proposed development access driveways. Furthermore, based on the anticipated left turning traffic volumes into the two site access driveway, there is adequate que uing storage in the existing northbound N. Kimball Ave. left turn lanes. Driveway Location and Spacing – the locations and spacing of the two development driveways meet the City’s requirements, except for the distance between Southlake Glen Dr. and the p roposed development Driveway 2. Because this driveway is proposed to be located at an existing median opening, a variance request to accept the sub -standard spacing is desirable. Driveway Sight Distances – More than adequate unobstructed sight distance will be provided at the two development access driveways. Driveway Internal Storage/ Throat Length - Based on the driveway queuing analysis results, a variance request to accept the sub -standard internal exiting vehicle storage length is desirable. Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 12 of 42 September 5, 2017 Appendices Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 13 of 42 September 5, 2017 Appendix A Traffic Counts Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 14 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 15 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 16 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 17 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 18 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 19 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 20 of 42 September 5, 2017 Appendix B Development Trip Generation Rates Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 21 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 22 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 23 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 24 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 25 of 42 September 5, 2017 Appendix C Synchro Traffic Capacity Analysis Worksheets Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 26 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 27 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 28 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 29 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 30 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 31 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 32 of 42 September 5, 2017 Appendix D Relevant Excerpts from the City of Southlake Access Management Standards and the TxDOT Access Management Manual Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 33 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 34 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 35 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 36 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 37 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 38 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 39 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 40 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 41 of 42 September 5, 2017 Revised Traffic Impact Analysis: Proposed Medical-Dental & General Office Development in Southlake, Texas Page 42 of 42 September 5, 2017