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HomeMy WebLinkAboutTR_Traffic_Impact_Analysis_Report_091016.pdfWILSON PARK PLAT TRAFFIC IMPACT ANALYSIS CITY OF RENTON Prepared for Mr. Robert Wilson 21703 601h St. E. Lake Tapps, WA 98391 Prepared by 717qff4FX . TRAA-F-1 C EXPi-R r.5 11410 N E 124" St., #590 Kirkland, Washington 98034 Telephone: 425.522.4118 Fax: 425.522.4311 June 23, 2009 rraffzmy June 23, 2009 Mr. Robert Wilson 21703 601h St. E. Lake Tapps, WA 98391 Re: Wilson Park Short Plat - City of Renton Traffic Impact Analysis Dear Mr. Wilson: N©RTH- -.5T TRAFF/C jEXPERTS 42=-.522 4' 19 Fax: 425,522 4311 We are pleased to present this traffic impact analysis report for the proposed 14 lot Wilson Park Residential short plat located at the 720 S. 55th St. in the City of Renton. The scope of this analysis is based upon the preliminary plat site plan, the City of Renton Policy Guidelines for Traffic Impact Analysis_for New Development, and conversations with City Renton staff. Our summary, conclusions and recommendations begin on page seven of this report. PROJECT DESCRIPTION Figure 1 is a vicinity map showing the location of the site and study area. Figure 2 is a close in area map showing the site location and surrounding street network. Figure 3 shows the preliminary site plan. The primary access street runs from the southwest corner of the site to S 55th St. through a 50 ft. wide easement on the parcel adjacent to the south side of the site. The primary access from S. 55th St. to the site is 28 ft. wide with a sidewalk on the west side of the street. A secondary gated emergency vehicle access connects to S 55th St. though a 30 ft. easement. Streets within the site will be 32 ft. wide with a sidewalk on one side. The primary site access street is located on the outside of a horizontal curve on S55 th St. to optimize sight distance in both east and west directions for vehicles exiting the site. Page 1 rra Development of the Wilson Park plat is expected to occur by the year 2011. Therefore, for purposes of this study, 2011 is used as the horizon year for this study. An existing single family home within the project site will be removed with this development. TRIP GENERATION AND DISTRIBUTION The 14 single-family units in the proposed Wilson Park Plat are expected to generate the vehicular trips during an average weekday and during the street traffic peak hours as shown below: Time Period Trip Rate Trips Trips Total Trips per unit Entering Exiting 67 67 Average Weekday 9.67 134 50% 50% AM Peak Hour 0.75 25% 811 75% PM Peak Hour 1.01 63% 514 37% A vehicle trip is defined as a single or one direction vehicle movement with either the origin or destination (exiting or entering) inside the study site. The trip generation is calculated using the average trip rates in the Institute of Transportation Engineers (ITE) Trip Generation, Eighth Edition, for Single Family Detached Housing (ITE Land Use Code 210). These trip generation values account for all site trips made by all vehicles for all purposes, including resident, visitor, and service and delivery vehicle trips. Figure 4 shows the estimated trip distribution and the calculated site -generated traffic volumes. The distribution is based on existing traffic volume patterns, the characteristics of the road network, the location of likely trip origins and destinations employment, shopping, social and recreational opportunities), expected travel times, and previous traffic studies. Page 2 Wilson Park rraffmy EXISTING PHYSICAL CONDITIONS Street Facilities Figure 5 shows existing traffic control, number of street lanes and other pertinent information. The streets in the study area are classified per the City of Renton Comprehensive Plan as follows: Talbot Rd. S Collector Arterial S 55th St. Local Access 98th Ave S Local access 98th PI. S Local access 102" d Ave S Local access S55 th St. consists of two 11 ft. lanes and a shoulder that varies in width from approximately two to four feet in the vicinity of the project site. A section of S 55th St. east of the project site consists of several sharp curves and is posted with a 15 mph advisory speed sign and with chevron arrows at each curve within the section. There is a left turn pocket on S 55th St. at 98th Ave. S, approximately 125 ft. west of the Wilson Park site access street. EXISTING TRAFFIC CONDITIONS Traffic Volumes Figure 6 shows existing, future without project and future with project PM peak hour traffic volumes at the proposed site access street/S 55th St. intersection. The proposal generates less than 30 PM peak hour trips and no other intersection or street segment in the City of Renton will experience an increase of 5% in traffic volumes due to this development. Therefore, only the site access street/S 55th St. intersection requires a level of service (LOS) analysis per the City of Renton Policy Guidelines for Traffic Impact Analysis for New Development, A PM peak hour traffic count was performed on Tuesday, June 16, 2009 and is included in the Technical Appendix. Level of Service Analysis Level of Service (LOS) is a qualitative measure describing operational conditions within a traffic flow, and the perception of these conditions by drivers or passengers. These conditions include factors such as speed, delay, travel time, freedom to maneuver, traffic interruptions, comfort, convenience, and safety. Levels of service are given letter designations, from A to F, with LOS A representing the best operating conditions (free flow, little delay) and LOS F the worst (congestion, long delays). Page 3 Wilson Park ifaffmy Generally, LOS A and B are high, LOS C and D are moderate and LOS E and F are low. Table 1 shows calculated level of service (LOS) for future conditions including project traffic at the pertinent street intersection. The LOS was calculated using the procedures in the Transportation Research Board Highway Capacity Manual 2000. The LOS shown indicates overall intersection operation. At intersections, LOS is determined by the calculated average control delay per vehicle. The LOS and corresponding average control delay in seconds are as follows: TYPE OF INTERSECTION A B C D E F 10.0 and 20.0 and 35.0 and 55.0 and X80. Signalized 10. 20.0 35.0 55.0 80.0 0 0 Stop Sign Control 1 10 and X15 X15 and <25 X25 and <35 35 and X50 50 Accident History Historical accident data for the section of S. 55th St. between the intersections 98th Ave. S and 991h Pl S was obtained from the City of Renton. A total of 4 accidents occurred from January 1, 2004 through December 31St 2008. Three accidents occurred on the street section between the intersections, one accident occurred at 99th Pi S and no accidents occurred at 98th Ave. South. Two of the accidents were injury type accidents with one being a fatality. The fatality was a single vehicle travelling in the westbound direction approximately 319 ft west of 99th PI. South. None of the accidents occurred at the curve on S. 55th St. where the site access street is proposed to be located. Based on the field review and historical accident data there are no readily apparent safety issues that should result from the proposed development. The historical accident data is included in the technical appendix. FUTURE TRAFFIC CONDITIONS WITHOUT THE PROJECT Figure 6 shows projected 2011 PM peak hour traffic volumes without the project. These volumes include the existing traffic volume counts plus background traffic growth. The background growth factor accounts for traffic volumes generated from other approved but unbuilt subdivisions and general growth in traffic traveling through the area. A 3% per year annual background growth rate was added for each year of the two year time period from the 2009 traffic count to the 2011 horizon year of the Page 4 Wilson Park rraffm, proposal. Cit of Renton historical traffic count data supports the 3% per year growth rate on S. 55t Street. FUTURE TRAFFIC CONDITIONS WITH PROJECT Figure 6 shows the projected future 2011 PM peak hour traffic volumes with the proposed project. The site -generated PM peak hour traffic volumes shown on Figure 4 were added to the projected future without project volumes to obtain the future with project volumes. Table 1 shows calculated LOS for future with project volumes at the Wilson Park site access street/S. 55th St. intersection. The study intersection operates at an excellent LOS A for future 2011 conditions including project -generated traffic. SIGHT DISTANCE EVALUATION Sight distance on S 551h St. is excellent looking to the west from the proposed site access street and extends approximately 785 ft. to Talbot Rd. South. Sight distance to the east is limited by a horizontal curve on S 55th Street. This curve has a posted advisory speed of 15 mph. In evaluating sight distance, the generally accepted rule is to add 5 mph to the posted speed to determine the design speed of the street. Sight distance requirements looking to the east from the Wilson Park site access street are therefore based on a 20 mph design speed for the horizontal curve on S 55th Street. Intersection sight distances and stopping sight distances were measured and compared to City requirements at the Wilson Park site access street/ S 55th St. intersection. City of Renton is requirements are based on current AASHTO "Geometric Design of Highways and Streets" standards. Intersection Siaht Distance AASHTO standards for a 20 mph design speed require an intersection sight distance of 145 ft. looking to the left (east) from the site access street (using an eye height of 3.5 ft. and a vehicle height of 4.25 ft.). Attached in the technical appendix are Exhibits 9-55 and 9-58 showing the current AASHTO standards for intersection sight distance. A right turning vehicle exiting from the side street is required to enter the westbound lane and accelerate to 85% of the design speed so as not to interfere with the traffic flow. The field measured intersection sight distance looking to left (east) from the site access street is 215 ft. thus exceeding the AASHTO required 145 feet. Intersection sight distance looking to the right from the site access street is excellent and extends all the way to Talbot Rd. S at approximately 785 ft. Page 5 Wilson Park r affmi Stopping Sight Distance Stopping sight distance is the distance traveled while the vehicle driver perceives a situation requiring a stop, realizes that stopping is necessary, applies the brake, and comes to a stop. A stopping sight distance of 115 ft. is required for a 20 mph design speed (using an eye height of 3.5 ft. and an object height of 2 ft.). Attached in the technical appendix is Exhibit 3-1 showing the current AASHTO standards for stopping sight distance. There is an approximate 10% downgrade in the westbound direction on S55 1h Street. The required stopping sight distance is therefore increased an additional 40 ft. to account for a 10% downgrade with a 20 mph design speed. The required westbound stopping sight distance therefore is 115 + 40 = 155 feet. The field measured westbound stopping sight distance is 197 ft. thus exceeding the required 155 feet. Stopping sight distance for eastbound vehicles on S. 55th St. is excellent and extends from Talbot Rd. S. approximately 785 feet to the site access street. The City of Renton AASHTO based intersection and stopping sight distance requirements are met at the Wilson Park site access street/ S 55th St. intersection in both the east and west directions. TRAFFIC MITIGATION REQUIREMENTS The City of Renton requires a Transportation Mitigation Fee payment of $75 per new daily trip attributed to new development. One existing single family home on site will be removed with this development resulting in a net increase of 13 single family homes. The net new daily trips due to this development are 124 trips (13units x 9.57 daily trips per unit). The estimated Transportation Mitigation Impact Fee is $9,300 (124 daily trips X $75 per daily trip). Page 6 Wilson Park Traffay SUMMARY, CONCLUSIONS AND RECOMMENDATIONS We recommend that the Wilson Park Plat be constructed as shown on the site plan with the following traffic impact mitigation measures: Construct the street improvements including curb, gutter and sidewalk for site access street and internal site streets as shown on the site plan. Contribute the approximately $9,300 Transportation Mitigation fee to the City of Renton. No other traffic mitigation should be necessary. If you have any questions, please call 425-522-4118. You may also contact us via e-mail at vinceCa?nwtraffex.com or larrygnwtraffex.com. Very truly yours, F Vincent J. Geglia Principal TraffEx Page 7 o r r W 104Z3 - Larry D. Hobbs, P.E. Principal TraffEx TABLE 1 PM PEAK HOUR LEVEL OF SERVICE SUMMARY WILSON PARK PLAT TRAFFIC IMPACT ANALYSIS INTERSECTION EXISTING 2009 WITHOUT 2077 WITH PROJECT PROJECT Site Access SCIS 55th St. NA NA SB (A 9.9) Number shown is the average control delay in seconds per vehicle for the worst approach or movement which determines the LOS for an unsignalized intersection per the Transportation Research Board Highway Capacity Manual 2000 XX) LOS and average control delay for the worst approach or movement at an unsignalized intersection SB) southbound approach Page 8 Wilson Park Plat - City of Renton Vicinity Map Figure 1 Traff r ° ! NORTHWEST ice' • , r s ... • TRAFFIC EXPEf?7 S I t.+ k •,,z33 04 ST 1 1 PY x . r ? A L 41 Veto L SYR. , e I f moi • .. I+ i y x . Ar' . --" ak F : ' • F *,r t.,' ice:- T Rento164. r` .. A 17 R-6 R-6mow t Fehr. ! j•Ai'1 "!r- s _# +j Wilson Park Plat - City of Renton Area Map Figure 2 I fW h199Ya£uno, 16 1r 1 / I 13 12 1f a 10 I I .q J QQ 1,1 c 1' - - - 4'Y' `'•6.5,1 Sq R 'l,00 , 9 n, e0.99' a9.9J'• pf i l C \. 4,i 9 SawCw15 'G, -. _ j I I s,ase tan a fi J - gyp• ; e.3?sale I, vnssw e wr.u. t".r.x I CC 55 a 3, 5 'j W4, kJ l •_ LY Ff 1 -' i 1` NLL 0 01! N' OW A. a an .40 M oamla AD a ram Wilson Park Plat - City of Renton Site Plan Figure 3 65% t q2,4:; 51 S 5)K , 3. t 14% T J v 7J 2 Q -0-Q J iSEh St rra ff IV OR THWEST TPA F -F -IG' EXPE-R T.S S,.- Sr y 19)T,4 3T 7% 7G1% 3 4 14% 3 SE. 1414: ST 4 --o- PM Peak Hour Traffic Volume Enter 9 Exit 5 Total 14 Legend Legend 15% Percentage of Project Traffic 3 PM Peak Hour Traffic Volume Wilson Park Plat- City of Renton Figure PM Peak Hour Trip Generation and Distribution 4 rrd? ff 7-RAFFEfC EXPERTS EE. 121T=I FT Y St. i9)T,4 ST d] Q U) 4J Q E co CL 5 N N M 2 Lanes 2 Lanes sr s lsr:, 3T 15 mph 2 Lanes I, ST 25 mph — 25 mph a) L ig d SOE C1 @ E J U-) 1L[7 C'4 n N CV x r. r3 Legend 2 Lanes Number of travel lanes 25 mph Speed Limit Stop Sign Control 15 Advisory Speed Sign Wilson Park Plat - City of Renton Figure Existing Conditions 5 1 A2H4 -' S i s 5TZ; -. S 55T:I ST S !?i47 ST Existing J 0, 0 466-(D-121 ite Access/ S 55th St rraff IVORTHWE.ET ' TRA F FYC ExPE-p i -.s Si i4ff,1 ST 1 1 V;QN s :.T rn f h I r Future Without Project CD L 0" J 0 494-@-128 to Access! S 55th St. Future With Project 7 J ; 2 494 - 128 to Access/ S 55th St Wilson Park Plat - City of Renton Figure PM Peak Hour Volumes for Existing and Future Conditions 6 TECHNICAL APPENDIX Prepare_ .or: NW Traffex La Traffic Count Consultants, Inc. Phanc: (425) 861-8866 FAX: (425) 861-8877 L -Mail; ('Uinc@aol.com Intersection: 98th Ave S Q S 55th St Location: Renton WBE/DBE Date of Count: Checked By: Tues 6116109 LBP Time Interval From North on (SB) 98th Ave S From South on (NB) 913th Ave S From East on (WB) S 5th St From West on (EB) S 5th St Interval Total Endin at T L S R T L S R T L S R T L S R 6 4:15 P 0 0 0 0 0 1 0 1 0 2 29 0 0 0 08 1 122 4:30 P 0 0 0 0 0 0 0 0 1 1 24 0 1 0 77 1 103 4:45 P 0 0 0 0 0 0 0 2 0 1 32 0 0 0 109 0 1144 5:00 P 0 0 0 0 0 0 0 1 0 0 34 0 0 0 124 1 1 160 5:15P 0 0 0 0 0 0 0 0 0 0 17 0 0 1 0 118 3 138 5:30 P 0 0 0 0 0 2 0 0 0 1 36 0 0 0 112 0 151 5:45 P 0 0 0 0 0 1 0 1 0 1 23 0 0 0 108 1 135 6:00 P 0 0 0 0 0 0 0 0 0 0 29 0 0 0 80 1 110 6:15P 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6:30P 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6:45P 0 0 0 0 0 0 0 0 Q 1 0 0 0 0 0 0 0 0 7:00P 1 0 1 0 1 0 1 0 1 0 j 0 1 0 0 0 1 0 1 0 F-01 0 1 0 0 0 0 Total Survey 0 0 0 0 0 4 0 5 1 6 224 0 1 0 816 8 1063 Peak Hour: 4:30 PM to 5:30 PM Total 0 0 0 0 0 2 0 3 0 2 119 0 0 0 463_L4 593 Approach 0 5 121 467 593 HV nla We Na We 0.0% PHF n/a 0.63 0.82 0.93 0.93 r S 5th St S 5th St 121 I Pcd:_0_ 1f19 121 Bike! D I 587 588 1 0 Bike 467 I 463 4:30 PM to 5.30 PM 0 Ped 466 4 PET), Across: N S E W Ped 0 2 3 640 1.R PHF Peak Hour Volume INT 01 0 Bike 0 PIIF' %HV INT 02 0 ER 0.93 nla INT 03 0 L ° J Check WB 0.92 n1a INT 04 0 In: 593 NB 0.63 n1a INT 05 0 I1 Out: 593 SB nla n1a INT 06 No Peds 0 98th Ave S Intersection 0.93 0.0% INT 07 0 Bicycles From: N S E W INT 08 0 INT 01 0 Special Notes: INT 09 0 INT 02 0 INT 10 0 INT 03 0 INT 11 0 INF 04 0 INT 12 0 INT 05 0 01 01 ol 0 0 INT 06 0 INT 07 0 INT 08 2 2 01 21 2 TM01p09043 w s xa mAx& gs T Kum: 4 a @ R 22 a 22 a a s Lr, r`"'0 -WAY STOP CONTROL SUMM"7Y General Information Site Informatio Analyst Intersection Agency/Co. Jurisdiction Renton Date Performed 6/19/2009 Analysis Year 2011 Future with Project Analysis Time Period PM eak Project Descri tion East/West Street: S 55th St North/South Street: Site Access St Intersection Orientation: East-West IStudy Period hrs : 0.25 Vehicle Volumes and Adjustments Major Street Eastbound Westbound Movement 1 2 3 4 5 6 L T R L T R Volume 7 494 0 0 128 2 Peak -Hour Factor, PHF 0.93 0.93 0.93 0.93 0.93 0.93 Hourly Flow Rate, HFR 7 1 531 0 0 1 137 2 Percent Heavy Vehicles 0 0 Median Type Undivided RT Channelized 0 0 Lanes 0 1 0 0 1 0 Configuration LT TR Upstream Signal 0 0 Minor Street Northbound Southbound Movement 7 8 9 10 11 12 L T R L T R Volume 0 0 0 1 0 4 Peak -Hour Factor, PHF 0.93 0.93 0.93 0.93 0.93 0.93 Hourly Flow Rate, HFR 0 1 0 1 0 1 1 0 4 Percent Heavy Vehicles 0 0 0 0 0 0 Percent Grade (%) 0 0 Flared Approach N N Storage 0 0 RT Channelized 0 0 Lanes 0 0 0 0 0 0 Configuration LR Delay, Queue Length, and Level of Service Approach EB WB Northbound Southbound Movement 1 4 7 8 9 10 11 12 Lane Configuration LT LR v (vph) 7 5 C (m) (vph) 1457 738 VIC 0.00 0.01 95% queue length 0.01 0.02 Control Delay 7.5 9.9 LOS A A Approach Delay 9.9 Approach LOS A ICS2000TM Copyright (0 2000 University of Florida, All Rights Reserved Version 4.1 AASHTO-Geamerric Design 'ghways and Streets - - rime gap (a) at design speed of Design vehicle rnajor road Passenger Car 6.5 Single -unit truck 8.5 Combination truck 10.5 Note: Time gaps are for a stopped vehicle- to turn right onto or cross a two-lane highway with no median and grades 3 percent or less. The table values require adjustment as follows: For multilane highways: For crossing a major road with more than two lanes, add 0,5 seconds for passenger oars and 0.7 seconds for trucks for each additional lane to be crossed and for narrow medians that cannot store the design vehicle. For minor road approach grades; If the approach grade is an upgrade that exceeds 3 percent, acid 0.1 seconds for each percent grade. Exhibit 9-57. Time trap for Csrse B2 -Right Turn from Stoic and Case W-,-Cressing Maneuver Design sped ltrr h Iatric Intersection sight Stopping distance for sightassenger Cars distance ^ Calculated Design m rr m(mph)-ft Design speed LIS Customar Inte"etion sight Stopping distance for sight passenger cars distance Calculated Design ft ft 20 20 36,1 40 15 80 143.3 145 30 35 54.2 55 20 115 191.1 195 40 50 72.3 75 25 1555 236.9 240 v4 65 90.4 95 30 200 286.7 290 60 85 108.4 110 35 250 334.4 335 70 105 126.5 130 40 305 382.2 385 80 130 144.6 145 45 360 430.0 430 90 160 162.6 165 50 425 477.8 484 100 185 180.7 185 55 495 525.6 530 110 220 1W8 200 60 570. 573.3 575 120 250 216.8 220 65 645 621.1 625 130 285 234.9 235 70 730 668.9 670 75 820 716,6 720 8t] 910 764.4 765 Note: lntersectik)a sight distance shown is for a stopped passenger car to turn right onto or cross a two-lane highway with no median and gravies 3 percent or less. For other conditions, the titre gap must be adjusted and required sight distance recalculated. Exhibit 9-58. Design Intersection Sight Disia nce.--[ ase B2 -Right Turn From Stop and Case W -Grossing Maneuver 668 Inferserlions Note: Intersection sight distance shown is for a stops passenger car to tum left onto a two-lane highway with no median and grades 3 percent or less. For other conditions, the time gap must be adjusted and required sight distance recalculated. Exhibit 9-55. Design Intersection Sight Distance--- Case 1'31• ---Lein Turn From Stop Sight distance design for left turns at divided -highway intersections Ahould consider multiple design vehicles and median width. If the design vehicle used to determine sight distance for a divided -highway intersection is larger than a passenger car, then sight distance for left turns will need to be checked for that selected design vehicle and for smaller design vehicles as well. If the divided -highway traedian is wide enough to store the design vehicle with a clearance to the through lanes of approximately I m [3 ft] at tooth ends of the vehicle, no separate analysis for the departure sight triangle for left turns is needed on the minor -road approach for the near roadway to the left. In most cases, the departure sight triangle for right tarns (Case H2) will provide sufficient sight distance for a passenger car to cross the Dear roadway to reach the median. Possible exceptions are addressed in the discussion of Case B3. If the design vehicle can be stored in the trtedian with adequate clearance to the through lanes, a departure sight triangle to the right for left turns should be provided for that design vehicle turning left from the median roadway. Where the tnedian is not wide enough to store the design vehicle, a departure sight triangle should be provided for that design vehicle to turn left from the minor -road approach. The median width should be considered in determining the number of lanes to be crossed. The median width should be converted to egtiivalent lanes. For example, a 7.2-m t24 -ft] median should be considered as two Additional lanes to be crossed in applying the multilane highway adjustment for time Saps in Exhibit 9-54. Furthermore, a departure sight triangle for left turns from the median roadway should be provided for the largest design vehicle that can be stored on rrR Metric US custa tns w Intersection sight Intersection sight Stopping distance for Stopping distance for Design sight passenger cars Design sight passe er cars speed distance Calculated Design speed distance Calculated Design krn/h rrt m m JMph ft ft 1t 20 20 41.7 45 15 80 165.4 170 30 35 62.6 65 20 115 220.5 225 40 50 83.4 8Ei 25 155 275.6 50 65 104.3 105 30 200 330.8 335 60 as 125.1 130 35 250 385.9 ago 70 105 146.0 160 40 305 441.0 446 8o 130 166.8 170 45 360 496.1 500 90 160 187.7 190 50 425 551.3 555 104 185 208.5 210 Sea 495 606.4 610 110 224 229.4 230 60 570 6181.5 665 124 250 250.2 255 65 645 716.5 720 130 285 271.1 275 70 730 771.8 775 75 820 826.9 830 80 910 882.0 885 Note: Intersection sight distance shown is for a stops passenger car to tum left onto a two-lane highway with no median and grades 3 percent or less. For other conditions, the time gap must be adjusted and required sight distance recalculated. Exhibit 9-55. Design Intersection Sight Distance--- Case 1'31• ---Lein Turn From Stop Sight distance design for left turns at divided -highway intersections Ahould consider multiple design vehicles and median width. If the design vehicle used to determine sight distance for a divided -highway intersection is larger than a passenger car, then sight distance for left turns will need to be checked for that selected design vehicle and for smaller design vehicles as well. If the divided -highway traedian is wide enough to store the design vehicle with a clearance to the through lanes of approximately I m [3 ft] at tooth ends of the vehicle, no separate analysis for the departure sight triangle for left turns is needed on the minor -road approach for the near roadway to the left. In most cases, the departure sight triangle for right tarns (Case H2) will provide sufficient sight distance for a passenger car to cross the Dear roadway to reach the median. Possible exceptions are addressed in the discussion of Case B3. If the design vehicle can be stored in the trtedian with adequate clearance to the through lanes, a departure sight triangle to the right for left turns should be provided for that design vehicle turning left from the median roadway. Where the tnedian is not wide enough to store the design vehicle, a departure sight triangle should be provided for that design vehicle to turn left from the minor -road approach. The median width should be considered in determining the number of lanes to be crossed. The median width should be converted to egtiivalent lanes. For example, a 7.2-m t24 -ft] median should be considered as two Additional lanes to be crossed in applying the multilane highway adjustment for time Saps in Exhibit 9-54. 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