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Home My WebLink About11-25-16 Correspondence - MDT to Commission - Signal Warrants Study N 19th and 1-90 Eastbound Off Ramp MD7* Montana Department of Transportation Michael T. Tooley, Director Steve Bullock, Governor Butte District Office 3751 Wynne Avenue PO BOX 3068 Butte MT59702-3068 Friday, November 25, 2016 Z S v Bozeman City Council Suite 201, City Hall P.O. Box 1230 121 North Rouse Bozeman, Montana 59771 Subject: Signal warrants study N 19`h and 1-90 eastbound off ramp Dear Commissioners: A project has been programed to install a new signal at the 1-90 eastbound exit ramp to 191h Street. The attached study is the signal warrant analysis for this project, which is currently scheduled for letting in November 2018. As the schedule changes and progresses, we will keep you in the loop. If you have any questions or comments about this project, please contact Michael Grover, MDT's project manager, at 406.444.4188 or mgrover@mt.gov. Lee C. Alt Butte District Traffic Engineer copies: Jen Nelson, Joe Walsh, Danielle Bolan - Helena Traffic, Michael Grover- Helena Traffic An Equal Opportunity Employer I Montana Department of Transportation PADI* PO Box 201001 INAS ' °RIWIL Helena, MT 59620-1 00 1 Memorandum To: Jeff Ebert,P.E. Butte Dist-ict AdmnnStl'at01' �- _)) F! From:�� Danielle C. Bolan, P.E. Traffic Operations Engineer Date: October 28, 2016 BM Subject: I-90 EB Ramps &N 19 Ave - Bozeman j� Signal Warrant Analysis, A signal warrant study has been completed at the intersection N 19''Ave and the - stboun-d I-94-ramps in Bozeman. The eastbound off-ramp is experiencing poor levels of service and queueing in the peak hour, and analysis shows that a traffic signal is warranted at this location. Existing Site Conditions The intersection of N 19'11 Ave with the I-90 eastbound ramps is currently operated under two-way stop control,with stop signs on the ramps. The off-ramp �+ } ?I provides a left-turn lane and a right-turn lane. Northbound 19°i(U-1201) provides one through lane, and a dedicated right-turn lane. Southbound 19 f ' provides a through lane and a left-turn lane at the intersection, but widens out to include aleft-turn,two t i throughs, and a right-turn lane as it intersects Valley Center Dr.The posted speed on 19°1 Ave is 40mph. r; Figure 1 provides an aerial view of the site. .+ Traffic Volumes >� Six hours of turning movement counts were collected tz by MDT in April 2014 from 7:00-9:00am, 11:30am- „' 1:30pm and 4:00-6:00pm. The morning peak hour occurred from 7:30-8:30am, } .YP and the evening peak from 5:00-6:00pni. Peak hour ��-� s volumes are shown in Figure 2. Signal Warrant Analysis: 1-90 EB Ramps &N 19°i Ave- Bozeman Page 2 of 4 Figure 1—Study Site Location: N 19`h Ave&EB 1-90 Ramps EB 1-90 Ramps & N 19th Ave EB 1-90 Ramps & N 19th Ave EB 1-90 Ramps & N 19th Ave Morning Peak 7:30-8:30am Noon Peak 11:45am-12:45pm Evening Peak 4:45-5:45pm 543 424 531 } L o � m v' O r ifl ¢) ift z z z EB On-Ramp EB On-Romp E8 On-Ramp 8 7 A27 0 0 N 0 Vl !n 302 267 EB Off-Ramp EB Off-Ramp EB Off-Romp N N N tD O > M N lf1 N m N 508 c 716 ± N �077 Z � Z Figure 2—Peak Hour Turning Movements Crash History During the five year period from July 1, 2010 through June 30, 2015, a total of 9 intersection-related crashes were reported at this location, resulting in 3 injuries. Five of the crashes were rear-ends, and four were right-angle. Right-angle crashes can be considered addressable through signalization. A breakdown of crash type and circumstances is shown in Table 1. Table 1—Crashes from July 1,2010 to June 31,2015 iftol 1;J 0a]Rt K 1 7/15/2010 11:48 THU Rear-End EB PDO Clear Dry Daylight 2 9/19/2012 11:45 WED Rear-End EB PDO Clear Dry Daylight 3 9/22/2012 20:32 SAT Right Angle NB+EB 1 Possible Clear Dry Dark-Lit 4 4/21/2013 15:59 SUN Rear-End EB PDO Cloudy Dry Daylight 5 7/2/2013 14:30 TUE Rear-End EB PDO Cloudy Dry Daylight 6 8/6/2013 00:00 TUE Rear-End EB 2lncapacitatinE Clear Dry Daylight 7 3/18/2014 08:42 TUE Right Angle NB+EB PDO Cloudy Ice/Frost Daylight 8 8/10/2014 17:20 SUN Right Angle NB+EB PDO Clear Dry Daylight 9 11/30/2014 12:15 SUN Right Angle SB+EB PDO Clear Snow Daylight Signal Warrant Analyses The Manual on Uniform Traffic Control Devices—2009 Edition (MUTCD)states that signalization of an intersection can be considered if one of the nine possible warrants is satisfied. Because traffic speeds on 19th exceed 40mph, 70% conditions were used for this analysis. Because only six hours of data was available, Signal Warrant 2 (Four-Hour Vehicular Volume)was the only warrant analyzed. The MUTCD states that right-turning vehicles entering the major street from an exclusive lane may be excluded from the calculations, if those vehicles are able to enter the major street with minimal conflict. Signal Warrant Analysis: 1-90 EB Ramps &N 19°i Ave - Bozeman Page 3 of 4 Observations of the intersection showed that queues of up to I I vehicles were experienced in the right- turn lane, indicating that some degree of conflict exists for this maneuver. Two scenarios were considered to determine what effect right-turning vehicles have on the outcome. The first scenario includes all turning vehicles in all lanes,the second excludes 50% of right-turns. Warrant 2 is satisfied under both scenarios(100% and 50% of right-turns.)The results are shown below. Warrant 2—Four-hour Vehicular Volume is satisfied if four of the plotted points representing vehicles per hour fall above the applicable curve for the existing combination of approach lanes. o All Ti•ajfic: SATISFIED,fully satisfied for all six hours, mainline numbers exceeded limits of chart for four hours. Hour 0 0 0 0 0 0 O O ,:_j N lD t� Both Approaches 936 902 1111 1113 1390 1595 Major Road Highest Approach 309 291 278 240 233 292 Minor Road = Y2 OR MORE LANES R 2 OR MORE LANES i w 0 2 OR MORE LANE5 R 1 LANELLJ CC � F-Q 1Cc i w C) Cc 1,60 20 3CO 400 50Cx c00 7CO 900 400 IWO MAJOR STREET--TOTAL OF BOThi APPROACHES— VEHICLES PER HOUR(VPI-I) o 50%Rights: SATISFIED,fully satisfied for all six hours, mainline numbers exceeded limits of chart for four hours. Hour 0 0 0 0 0 0 O O H N W n n 00 H e-1 14 11 Both Approaches 936 902 1111 1113 1390 1595 Major Road Highest Approach 161 153 144 126 117 156 Minor Road > I .,.�2 OR%1ORE LANES&2 OR V,ionE LAMES a - w 2 OR MORE LANES A i LAN . W i i rc �.Z 280 i _ i i LANE`-i LAWF �w O �j w ^r.3 3CO 40O 530 GCO 7CO S;r 99p 1000 MAJOR STRECT—TOTAL OF BOTI I APPROACI iES— VEI IIGLES PER I LOUR(VPI1) Signal Warrant Analysis: I-90 EB Ramps & N 19"' Ave - Bozeman Page 4 of 4 Capacity Analysis Capacity analysis of the intersection was performed using HCS2010 and Sidra software. The morning and evening peak volumes were used to calculate the Level of Service(LOS) and delay at the intersection N 19"Ave 1-90 Off-Ramp under two-way stop conditions. SB EB AM Peak Hour Left Left Right Analysis shows that the ramp currently Volume/Capacity 0.14 0.06 0.68 operates at an overall LOS D in the morning 95%Queue(veh) >1 >1 5.06 and evening peaks. The eastbound left-turn Delay(sec) 9.5 32.3 25.4 movement operates at a failing LOS in the Level-of-Service A D D evening peak. Approach Delay 25.6 Approach LOS D PM Peak Hour Left Left Right Conclusion Volume/Capacity 0.08 0.29 0.60 Peale-hour queueing is occurring on the 95%Queue(veh) >1 1.08 3.92 eastbound I-90 off-ramp, and capacity analysis Delay(sec) 11.8 66.1 22.6 Level-of-Service B F C indicates a LOS D during the AM and PM Delay 2S g peaks. Signal Warrant 2 (four-hour vehicular Approach Approach Del p volume) is satisfied, and signalization could address the four right-angle crashes. Recommendation Installation of a traffic signal is recommended at N 19°i Ave and the EB I-90 Ramps. This signal should be timed in coordination with the existing signals on the N 19"'Ave corridor. ZC I concur: Date Roy A. Peterson, P.E. Traffic& Safety Engineer DCB:TLK: I90 EB RAMPS 19TH MEMO.docx Copies : Jennifer Nelson—Butte District Lee Alt—Butte District Mike Grover—Traffic& Safety Dan Cunningham—Traffic & Safety Tasha King—Traffic& Safety Traffic & Safety File