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HomeMy WebLinkAbout017 Gran Cielo Subdivision TIS Update - Stucky Road MARVIN & ASSOCIATES 1300 N. Transtech Way Billings, MT 59102 Mailing Address: P.O. Box 80785 Billings, MT 59108-0785 Phone: 406-655-4550 FAX: 406-655-4991 Email: bobm@marvinassociates.com Erik Ringsak, EI Madison Engineering, LLC 895 Technology Blvd, Suite 203 Bozeman, MT 59718 August 24, 2023 Re: Gran Cielo Subdivision TIS Update The City of Bozeman staff has required that a westbound left-turn lane be constructed on Stucky Road at its intersection with S 27th Avenue to mitigate development traffic impacts associated with Gran Cielo Subdivision. In order to determine if the required left turn lane is warranted based on current and future conditions at this intersection Marvin & Associates has prepared an update to the original TIS prepared in October of 2017. Please allow this letter, which focuses on the intersection of Stucky Road and S 27th Avenue intersection, to serve as an update to the original TIS. Traffic Volumes MioVision traffic counts were taken in August 2023 and a summary of the counts at the subject intersection is attached to this report. In order to determine the average peak hour traffic currently experienced at this intersection, the counts had to be adjusted by seasonal adjustment factors. Montana Department of Transportation (MDT) data for its continuous count stations was used to determine the annual average traffic volumes. It was determined that average weekday traffic in August is approximately 10% higher than the annual average weekday traffic. Therefore, the count volumes were annualized using a factor of 0.90. The figure below represents the adjusted traffic volumes in the peak AM and PM hours used within this analysis. MARVIN & ASSOCIATES 1300 N. Transtech Way Billings, MT 59102 Mailing Address: P.O. Box 80785 Billings, MT 59108-0785 Phone: 406-655-4550 FAX: 406-655-4991 Email: bobm@marvinassociates.com Distribution & Traffic Assignment The original TIS trip distribution percentages at this intersection were modified to account for the magnitude of development that has occurred on the western fringe areas of Bozeman during the past 6 years. The traffic reflects the directional distribution of trips being generated in the Gran Cielo Subdivision. Approximately 69% of the trips and directed to and from the west and the remaining 31% of trips are directed to and from the east. This distribution was used to assign full development traffic at the subject intersection. It has been assumed that full development of the Gran Cielo Subdivision and other adjacent subdivisions will take approximately 10 years. Therefore, future traffic projections were made based on an annual average growth rate of 2% for through traffic volumes on Stucky Road. Projected traffic volumes during the peak AM and PM hour for the future year 2033 are illustrated in the figure below. Auxiliary Turn Lane Impacts Attached are turn lane nomographs extracted from the MDT Traffic Engineering Manual which provides guidelines to determine whether auxiliary turn lane should be considered or not. The specific left turn lane nomograph used in the analysis was for a design speed of 45 mph. The posted speed limit on Stucky Road is 40 mph and the lower speed limit should be a consideration in whether the left turn lane is justified. For existing conditions, the left turn lane on Stucky Lane is left of the warranting line for 5% left turn volume line and would not be warranted either in the peak AM hour or the Peak PM hour. Future traffic projections for the year 2033 have an intercept point to the right of the 5% warrant line and would therefore meet the warrant values required for consideration of a left turn lane. The only situation that could possibly meet warrants or a right turn lane at the subject intersection would be the eastbound right turn movement during the peak PM hour in the year 2033. The warranting volumes intercept point is slightly left of the warrant line for a right turn lane and would therefore not meet that warrant. MARVIN & ASSOCIATES 1300 N. Transtech Way Billings, MT 59102 Mailing Address: P.O. Box 80785 Billings, MT 59108-0785 Phone: 406-655-4550 FAX: 406-655-4991 Email: bobm@marvinassociates.com Capacity Impacts Intersection capacity based on the current geometrics was an additional consideration that was considered. Capacity calculations were completed for the peak AM and PM hours and are attached to this report. For existing conditions, the peak PM hour would have the highest average vehicle delay (16.9 seconds) for the northbound approach, which operates at a level of service LOS) “C”. In the year 2033, that approach would have 23.4 seconds average delay and still be within the LOS “C” range. The longest vehicle queue would be 1 vehicle on the northbound approach. The calculated vehicle queue for the westbound left turn lane was 0.1 vehicles in the year 2033. In practical terms, there is a good possibility that 1 vehicle will need to be stored in the through westbound lane (with low frequency), but that vehicle would not substantially impact the LOS “A” projected for westbound through traffic. Conclusions Our analysis of auxiliary turn lanes on Sucky Road at its intersection with S 27th Avenue indicates that auxiliary turn lanes are not currently warranted at the intersection of Stucky Road and S 27th Avenue. However, the warranting values for a westbound left turn lane on Stucky Road would be met within the next 10 years and consideration of implementing the auxiliary turn should be given. It should also be noted that in the year 2033 the AWT on Stucky Road will be approximately 10,000, which would exceed the ideal capacity of a two lane roadway. Reconstruction of Stucky Road to provide at least 3 lanes prior to 2033 should be considered. If additional information is desired, feel free to contact me. Robert R. Marvin, P.E., P.T.O.E. TotalStart Time Right Thru Left Right Thru Left Right Thru Left Right Thru Left Entering7:00 AM 51 5 1 4 2 47 1107:15 AM 66 1 0 5 1 76 1497:30 AM 67 2 2 6 2 84 1637:45 AM 69 2 3 4 6 121 2058:00 AM 55 1 2 3 5 94 1608:15 AM 79 0 4 7 2 96 1888:30 AM 68 1 1 5 2 85 1628:45 AM 70 2 5 7 5 97 186Peak AM Total =270 5 11 0 20 15 395 0 716PHF = 0.874:00 PM 111 2 6 9 7 85 2204:15 PM 95 4 4 5 5 80 1934:30 PM 105 3 2 3 0 89 2024:45 PM 127 3 2 6 7 80 2255:00 PM 157 3 2 6 4 92 2645:15 PM 109 3 1 6 8 110 2375:30 PM 122 8 0 5 4 103 2425:45 PM 73 8 0 3 3 96 183Peak AM Total =515 17 5 0 23 23 385 0 968PHF = 0.92Southbound Westbound Northbound EastboundType RoadClassification Totalsn/a Stucky Road S 27th Avenue Stucky RoadSite CodeProject Gran Cielo TIS UpdateStudy Name 27th & Stucky Start Date 08/15/2023Start Time 7:00 AM HCS Two-Way Stop-Control Report General Information Site Information Analyst R Marvin Intersection Stucky Road & S 27th Avenue Agency/Co.Marvin & Associates Jurisdiction City of Bozeman Date Performed 8/24/2023 East/West Street Stucky Road Analysis Year 2023 North/South Street S 27th Avenue Time Analyzed AM Hour Existing Peak Hour Factor 0.87 Intersection Orientation East-West Analysis Time Period (hrs)0.25 Project Description Gran Cie;o TIS Update Lanes Major Street: East-West Vehicle Volumes and Adjustments Approach Eastbound Westbound Northbound Southbound Movement U L T R U L T R U L T R U L T R Priority 1U 1 2 3 4U 4 5 6 7 8 9 10 11 12 Number of Lanes 0 0 1 0 0 0 1 0 0 1 0 0 0 0 Configuration TR LT LR Volume (veh/h)355 15 5 245 20 11 Percent Heavy Vehicles (%)0 0 0 Proportion Time Blocked Percent Grade (%)0 Right Turn Channelized Median Type | Storage Undivided Critical and Follow-up Headways Base Critical Headway (sec)4.1 7.1 6.2 Critical Headway (sec)4.10 6.40 6.20 Base Follow-Up Headway (sec)2.2 3.5 3.3 Follow-Up Headway (sec)2.20 3.50 3.30 Delay, Queue Length, and Level of Service Flow Rate, v (veh/h)6 36 Capacity, c (veh/h)1145 462 v/c Ratio 0.01 0.08 95% Queue Length, Q₉₅ (veh)0.0 0.2 Control Delay (s/veh)8.2 0.0 13.4 Level of Service (LOS)A A B Approach Delay (s/veh)0.2 13.4 Approach LOS A B Copyright © 2023 University of Florida. All Rights Reserved. HCS™TWSC Version 2023 Generated: 8/24/2023 12:31:35 AMS 27th & Stucky AM Exist.xtw HCS Two-Way Stop-Control Report General Information Site Information Analyst R Marvin Intersection Stucky Road & S 27th Avenue Agency/Co.Marvin & Associates Jurisdiction City of Bozeman Date Performed 8/24/2023 East/West Street Stucky Road Analysis Year 2023 North/South Street S 27th Avenue Time Analyzed PM Hour Existing Peak Hour Factor 0.92 Intersection Orientation East-West Analysis Time Period (hrs)0.25 Project Description Gran Cie;o TIS Update Lanes Major Street: East-West Vehicle Volumes and Adjustments Approach Eastbound Westbound Northbound Southbound Movement U L T R U L T R U L T R U L T R Priority 1U 1 2 3 4U 4 5 6 7 8 9 10 11 12 Number of Lanes 0 0 1 0 0 0 1 0 0 1 0 0 0 0 Configuration TR LT LR Volume (veh/h)330 23 17 465 23 5 Percent Heavy Vehicles (%)0 0 0 Proportion Time Blocked Percent Grade (%)0 Right Turn Channelized Median Type | Storage Undivided Critical and Follow-up Headways Base Critical Headway (sec)4.1 7.1 6.2 Critical Headway (sec)4.10 6.40 6.20 Base Follow-Up Headway (sec)2.2 3.5 3.3 Follow-Up Headway (sec)2.20 3.50 3.30 Delay, Queue Length, and Level of Service Flow Rate, v (veh/h)18 30 Capacity, c (veh/h)1186 332 v/c Ratio 0.02 0.09 95% Queue Length, Q₉₅ (veh)0.0 0.3 Control Delay (s/veh)8.1 0.2 16.9 Level of Service (LOS)A A C Approach Delay (s/veh)0.5 16.9 Approach LOS A C Copyright © 2023 University of Florida. All Rights Reserved. HCS™TWSC Version 2023 Generated: 8/24/2023 12:35:56 AMS 27th & Stucky PM Exist.xtw HCS Two-Way Stop-Control Report General Information Site Information Analyst R Marvin Intersection Stucky Road & S 27th Avenue Agency/Co.Marvin & Associates Jurisdiction City of Bozeman Date Performed 8/24/2023 East/West Street Stucky Road Analysis Year 2033 North/South Street S 27th Avenue Time Analyzed AM Hour Future Peak Hour Factor 0.87 Intersection Orientation East-West Analysis Time Period (hrs)0.25 Project Description Gran Cie;o TIS Update Lanes Major Street: East-West Vehicle Volumes and Adjustments Approach Eastbound Westbound Northbound Southbound Movement U L T R U L T R U L T R U L T R Priority 1U 1 2 3 4U 4 5 6 7 8 9 10 11 12 Number of Lanes 0 0 1 0 0 0 1 0 0 1 0 0 0 0 Configuration TR LT LR Volume (veh/h)425 21 9 290 63 27 Percent Heavy Vehicles (%)0 0 0 Proportion Time Blocked Percent Grade (%)0 Right Turn Channelized Median Type | Storage Undivided Critical and Follow-up Headways Base Critical Headway (sec)4.1 7.1 6.2 Critical Headway (sec)4.10 6.40 6.20 Base Follow-Up Headway (sec)2.2 3.5 3.3 Follow-Up Headway (sec)2.20 3.50 3.30 Delay, Queue Length, and Level of Service Flow Rate, v (veh/h)10 103 Capacity, c (veh/h)1063 376 v/c Ratio 0.01 0.28 95% Queue Length, Q₉₅ (veh)0.0 1.1 Control Delay (s/veh)8.4 0.1 18.2 Level of Service (LOS)A A C Approach Delay (s/veh)0.4 18.2 Approach LOS A C Copyright © 2023 University of Florida. All Rights Reserved. HCS™TWSC Version 2023 Generated: 8/24/2023 12:38:04 AMS 27th & Stucky AM Future.xtw HCS Two-Way Stop-Control Report General Information Site Information Analyst R Marvin Intersection Stucky Road & S 27th Avenue Agency/Co.Marvin & Associates Jurisdiction City of Bozeman Date Performed 8/24/2023 East/West Street Stucky Road Analysis Year 2033 North/South Street S 27th Avenue Time Analyzed PM Hour Future Peak Hour Factor 0.92 Intersection Orientation East-West Analysis Time Period (hrs)0.25 Project Description Gran Cie;o TIS Update Lanes Major Street: East-West Vehicle Volumes and Adjustments Approach Eastbound Westbound Northbound Southbound Movement U L T R U L T R U L T R U L T R Priority 1U 1 2 3 4U 4 5 6 7 8 9 10 11 12 Number of Lanes 0 0 1 0 0 0 1 0 0 1 0 0 0 0 Configuration TR LT LR Volume (veh/h)395 77 33 560 42 18 Percent Heavy Vehicles (%)0 0 0 Proportion Time Blocked Percent Grade (%)0 Right Turn Channelized Median Type | Storage Undivided Critical and Follow-up Headways Base Critical Headway (sec)4.1 7.1 6.2 Critical Headway (sec)4.10 6.40 6.20 Base Follow-Up Headway (sec)2.2 3.5 3.3 Follow-Up Headway (sec)2.20 3.50 3.30 Delay, Queue Length, and Level of Service Flow Rate, v (veh/h)36 65 Capacity, c (veh/h)1063 260 v/c Ratio 0.03 0.25 95% Queue Length, Q₉₅ (veh)0.1 1.0 Control Delay (s/veh)8.5 0.4 23.4 Level of Service (LOS)A A C Approach Delay (s/veh)0.9 23.4 Approach LOS A C Copyright © 2023 University of Florida. All Rights Reserved. HCS™TWSC Version 2023 Generated: 8/24/2023 12:34:55 AMS 27th & Stucky PM Future.xtw