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Home My WebLink AboutSDP202000052 Study Traffic Study 2020-06-10SHIMP ENGINEERING, P.C. Design Focused Engineering Warrant Analysis Albemarle County TMPs 75-66 & 76-17 Regents School of Charlottesville June 10, 2020 912 E. High St. Charlottesville, VA 22902 1434.227.5140 1 shimp-engineering.com Contents: 1. Project Narrative 2. Trip Generation & Distribution 3. Warrant Analysis 4. Conclusion 1. Project Narrative The proposed entrance is located on the southern side of State Route 702 Reservoir Road in Albemarle County. This entrance is to serve a private school with enrollment of maximum 468 students; therefore the analysis of this entrance assumes maximum enrollment. Please note that the current site plan proposes 280 students, so trip generation figures may differ from the site plan. This analysis uses trip generation estimates from ITE 10`h Edition Trip Generation software to be conservative and is separate from the traffic study submitted for the operational changes request. For more detailed trip generation data, please refer to the October 12, 2018 analysis by EPR, P.C. Both left and right turn lane warrant analyses were conducted, and neither were found to be required for this project. Two key assumptions were made for these analyses: 1. A direction factor of 0.5 was assumed for the regular traffic (unrelated to the school) that exists on Reservoir Road. 2. A direction factor of 0.95 was assumed for traffic related to the school. This direction factor was assumed for traffic traveling towards the school in both the morning and the evening conditions. Reservoir Road is a dead end road with very few residences located west of the site. Our direction factor for school traffic assumes that most of the travel will be to and from Route 29. 2. Trip Generation & Distribution The turns into and out of the site were analyzed based on the 1 Oh Edition ITE Trip Generation estimates for a private school (K-12) with 468 students. Pairing this information with the assumed direction factor of 0.95 for school traffic produces the information found in Table 1 below. Table 1. ITE Trip Generation Summary ITE TripGen, 10th Edition AM PM Use Description ITE Qty in out Total in out Total Private School (K-12) 536 468 Students 228 146 374 34 46 80 Right Turn 11 2 Left Turn 217 33 The following figures are taken directly from the ITE Trip Generation web -based App, where we received data for trips into and out of the site. goEry Finer l Trip Gen Manual, 19tlr Ed dIt, e 111 Is available. Clidr hem ig upgrade. SEARCH BY — USE LODE: 536 0 IAXR USE GROUP: 50O- 599)Inslitugonal 536- private School (K-12) LAXU USE SUBCATEGORY: All SRes INDEFEDIDENT VARIJUBLE Irvh Students IW— W.y. Ft A Hour of Adjacent Street TralPX SETT WILOCATION: General DrbaNSuburban Vehicle E468R Iv vnwE To cA Calwlale, Data Plot and Equation Caution - Smarr Sample Srze w 3so F I, 3OD X study Site Figure 1. ITE Trip Generation AM Peak Hour 900 450 X = Number of Students Rese[ Zoom Res[ore Fitted Curve soo Average Rate DATA STATISTICS Private School (K-12) (536) Click rgr mgrI details IntlepentleM Venable: studen nine Period: Weekbey Peak Hour M AdJaee.t Street Tmfie One It— Between T OUT 9 a m SeWnglLoragon: Uenerel lJrben E—rean Tnp Type: Vehicle Number of Studies: 4 Avg. Num. of Students'. 5Dfi Average Re. 0. 80 Range of Rates: 049- 096 Standard Deviation'. 021 IF Curve Equation: T = g.eotx)- 3.5T Ra 063 heed— Dtstrmugon: 61% entering 39%eniing Calculated Trig, Ends: Avenge Rnte: 374(TMeI), 228 U,17 ,1W Ui PiXed Cu-: 371 (Trial), 226 (Erlhy), 145 (aft) Query Filter Trip Gen Manual, 101, Ed Nely dal. edum i5 available Cllck hen: to upgrade. S536cR ev uNo ®coDE. 50 g-699)Ins[dutional vl 536- Private Srdlodl (K-12) USE SVBOATEGOM All Sites p—NDE LE W: SWdelds Weekday, Peak Hour of AtlI .. Street TralNr s General Udtard&bulban Veh cle EdfipR IV VALUE To taCaluiate IP Data Plot and Equation caution- S—Ij samp)a size X loc X 50 pD __20D_______________40O ____ L__________ 600 ______ X = Numb—f 5tudents Reset Zoom Resmre X Study Site Figure 2. ITE Trip Generation PM Peak Hour Avuage Rate DATA STATISTICS d Use: Pdvale School (K-12) (536) CI Iuk for more tlelalle ndependent Mdable: Students Tme Period: Weekday Peak Hour of Mj....t Bbee1 Tmigc One Hour Between 4 and 6 pm. SeltinglL—b": General 11NaNSubulban Tnv Tyve: Vehlde Number of SW dies: 3 Avg. Num. of SWdenis: 581 Average R- R - of Rates: 013-02a Standard Deviatlnn. p06 Filled Cume Equation: Not Glven Rv' Direcdonal pistribuppn: 43% enledng, 57% a,iting CaInuIWLV Trip Ends: Average Rale'. 80 (Total). 34 (Erdry). 16 (Exu) 3. Warrant Analysis A right and left turn warrant analysis was performed for the proposed entrance using the trip generation information from the previous section in conjunction with VDOT 2018 Traffic Data. Please see the table below for the traffic data for State Route 702 Reservoir Road. Table 2. VDOT 2018 Traffic Data Reservoir Road 35 mph 1.7 mi section from 0.5 ME Dead end and 2.20 ME Dead End K D Assumed .5 AADT 400 Peak Hour Approaching 44 Note: K*D assumed 11% The right turns into the site are highest in the morning, with 11 trips. This traffic generated by the proposed school is added to the peak hour approach total for the right turn lane warrant analysis. Please see Figure 3 below for the results of the right turn lane warrant analysis. 120 1 ''.}},• {{ ••'}} ;•; FULL —WIDTH TURN LANE AND TAPER FIEF MM tiff =''•' ==.. _ Lij -':.}}'+';+;'}.{{:f}}{r{W};:}}}*,:,fir,•. i s 60 •TAPER REQLa1RED+ - y:;:•}:tip:•. ZE CL--------------------- 20 1 Q TUFEN L NT S --------------- OR TAPERS REQUIRED 11 55 I100 200 S00 400 Soo Soo 700 1 PHV APPROACH TOTAL, VEHICLES PER HOUR Appropriate Radius required at all Intersections and Entrances (Commercial or Private)- PHV - Peak Hour Volume (also Design Hourly VoIume equivalent) Adjustment for Right Turns Far posted speeds at or under 45 mph, PHV right turns > 40, and PHV fatal < 300- Adjusted right turns = P h V Right Turns - 20 If PHV is not known use formula: PHV = ADT x K x D K = the percent of AADT occurring in the peak hour D = the percent of traffic in the peak direction of flow Note: An average of 11% for K x D will suffice. When right turn facilities are warranted, see Figure 3-1 for design criteria FIGURE 3-26 WARRANTS FOR RIGHT TURN TREATMENT (2-LANE HIGHWAY) Figure 3. Warrant for Right Turn Taper Figure 3 shows that no right turn lane or taper is warranted for this site. For the left turn lane warrant analysis, the traffic generated by the proposed school is added to advancing and opposing volumes. The direction factor of baseline traffic on Reservoir Road is assumed to be 0.5, therefore the baseline peak hour advancing volume is equal to the peak hour opposing volume. Morning left turns were analyzed as this scenario produces the most trips with a total of 217 left turns into the site. This traffic added to the baseline peak hour of 44 trips gives an advancing volume of 261 (left turns comprise 43% of advancing volume). Morning right turns into the site plus the baseline traffic gives an opposing volume of 55 trips. Please see Figure 4 below for the left turn taper warrant. F-58 Warrants for Left Turn Storage Lanes on Two -Lune Highways Advancing volume and opposing volumes (VPH), speed and percent left turns are used to determine whethera left turn storage lane is warranted on two-lane highways_ The warrants in table below are taken from the 2011 AAS HTO Green Book, Chapter 9, Section 9.7.3, Page 9-132, Table 9-23. They were derived from Highway Research Report No. 211, Figures 2 through 19, for required storage length determinations. WARRANTS FOR LEFT TURN LANES ON TWO-LANE HIGHWAYS VPH ADVANCING VOLUME OPPOSING VOLUME 5%6 10%6 20% 311% LEFT TURNS LEFTTiIRIG LEFT TURNS LEFT TURNS 40-MPH DESIGN SPEED' BOD 33D 240 ia0 100 601) 41D 305 225 200 40D 51D 380 275 245 201) 54D 470 350 305 101) 72D 515 390 34U 54MPH DESIGN SPEED' BOD 28D 210 165 1W 00D 35D 280 195 170 401) 43D 320 240 210 201) 55D 4110 300 270 10D 015 445 335 295 94MPH DESIGN SPEED' 80D 23D 170 125 115 1001) 29D 210 1100 140 401) 365 270 2110 175 20D 45D 330 250 215 101) 505 370 275 240 TABLE 3-1 Source: Adapted from 2011 AAHTO Green Book, Chapter 9, Section 9.7.3, Page 9-132, Table 9-23 USE DESIGN SPEED IF AVAILABLE, IF NOT USE LEGAL SPEED LIMIT. Figure 4. Warrant for Left Turn Taper OPKINNG k ytlLLYE1VPFl) AD' CIHG HT7X1RN x+i4L4 P FU vOLuAEP+'W Example - Two -lane highway with 40-MPH operating speed opposing Volume (VPH) - 600 Advancing Volume (VPH) -440 Left -Turn Volume (VPH) - 44 or 10% of Advancing Volume With opposing volume (VPH) of 600 and 10 of advancing volume (VPH) making left turns, and advancing volume (VPH) of 305 or more will warrant a left -turn lane_ When the Average Running Speed on an existing facility is available, the corresponding Design Speed may be obtained from Appendix A, Section A-1. Advancing volume does not exceed 340 vehicles per hour, therefore a left turn taper is not warranted. 4. Conclusion Enrollment for Regents School at Reservoir Road is only permitted to reach a maximum of 468 students. Based on ITE Trip Generation, 10th Edition figures for this site in combination with VDOT 2018 Traffic Data for existing traffic on Reservoir Road, neither a right taper/turn lane nor left turn lane is warranted for this site. Please contact me with any questions or comments at (434)227-5140 or justin(&shimp-en ing eerieg com. Regards, Justin Shimp, PE