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Home My WebLink AboutCedar Spring N. Traffic Study . . ~~ CEDAR SPRINGS NORTH PLANNED UNIT DEVELOPMENT TRAFFIC IMPACT STUDY Prepared for J-U-B Engineers, Inc. 250 S. Beechwood Drive Boise, Idaho 83709 October 8, 2002 Prepared by G Washington Washington Infrastructure Services 720 Park Boulevard, P.O. Box 73 Boise, Idaho 83729-0073 (208) 386-5000 ~ . . Cedar Springs Traffic Impact Study INTRODUCTION Washington Infrastructure Services (WIS) has been retained to prepare a traffic impact study for the proposed Cedar Springs North planned unit development (PUD) located on the south side of W. McMillan Road between N. Linder Road and N. Meridian Road. Figure 1 displays the location of the project and its vicinity. The purpose of this report is to evaluate the traffic impacts resulting from the proposed development. This study will only make recommendations for the intersection of McMillan Road and the site access road. Recommended improvements to the transportation system in the vicinity of the project site are not included in this report; these issues have already been addressed in the North Meridian Area Traffic Study completed by WIS. This report is prepared in conformance with the requirements of a major traffic impact study as required by the Ada County Highway District (ACHD). However, as stated previously, issues already addressed in the North Meridian Area Traffic Study are not included. In particular, the scope of the study includes the following: . Trip generation ofthe proposed development; . Trip distribution and traffic assignment of the site generated traffic; . Impacts of site generated traffic at site access intersection; and . Recommendations for site access intersection. PROPOSED DEVELOPMENT Cedar Springs is a proposed PUD with 180 residential-single family dwelling units on an 81.5- acre site located on the south side of McMillan Road between Linder Road and Meridian Road. The proposed preliminary site plan for the project is presented in Figure 2. The study assumes that the development will be completely built by the year 2007. As shown in the preliminary site plan, the development proposes only one full-access onto McMillan Road. The site plan stubs three streets to the west properties, two streets to the east properties, and two streets to the south properties. STUDY AREA CONDITIONS Study Area The area of influence will be Ada County. The area of primary impact will be along McMillan Road. Linder Road and Meridian Road will also be impacted by the development. The intersection of the site access with McMillan Road will be evaluated for impacts. Refer to the North Meridian Area Traffic Study Report for impacts to the intersection of Linder Road with McMillan Road and the intersection of Meridian Road with McMillan Road. Land Use The project area is currently vacant and zoned as RUT. The site is proposed to be rezoned as R-4 (residential) and LO (limited office). G Washington Page] Cedar Springs TIS.doc . . W. CHINDEN BLVD. --- --'"-" - -'il I, r-'-~ 1 ~~ ~.",\ I ". '---~ ! -,'-. --~ I' ~ ~ , ~ I '.~ ~ -~ _.~--_.." ----- .~.~~ I , , I ~- ..~~~~ --, \, ", '-'\ \ " "'\, '. o <[ o _.__-. a:: a:: w o Z ...J " o <[ o a:: z <[ o a:: w L Z . Z -, ~ ' '~~""-..c-'["~ I~ ~. '. .~ ."'.. -~ c~o..=_=~",_=.y .- / [ "_ I _..~__~_.c~ . ) ~'" ~~ . \ "-- \ ~ I I! \ i~ ~........... __~__.. ::~.." '-~ __:- ..__W. USTICK ~ ------------ " ROAD 'Ulltl n. ~ J A SCl.t. Figure 1 .Vicinity Map Engineers: Cedar Springs P.U.D. t'~9V, .UTE D.rt,OCTO!lRZOID2 II. .SZI'I..H IfllI\a/JSD1/tEllIoA SI' 11M ~ Washington JUB . . w. McMILLAN ROAD ----- ~~ --., iODDD iD 0 0 ~ 1~ 000 ~ . 0 I . I , I I , [SIC~ BY,J.TH( n DeTDBU2efl2 Figure 2 Proposed Site Plan JUS Engineers: Cedar Springs P.U.D. RUIN 9';11 StAL(J . " ~ Washi';;~' ~'" . . Cedar Springs Traffic Impact Stltdy EXISTING CONDITIONS Traffic Volumes Refer to the North Meridian Area Traffic Study Report for the existing traffic counts and turning movements for the roadways in the vicinity ofthe project area. Road System The road system in the site vicinity is described below: . Linder Road is a two-lane north-south facility classified as a minor arterial. The posted speed limit is 50 mph. . Meridian Road is a two-lane north-south facility classified as a minor arterial. The posted speed limit is 50 mph. . McMillan Road is a two-lane east-west facility classified as a minor arterial. The posted speed limit is 50 mph. . The intersection of Linder Road with McMillan Road and the intersection of Meridian Road with McMillan Road are both all-way stop controlled intersections. STUDY PERIOD The build out year for this study was assumed to be 2007. Only the weekday p.m. peak hour period between 4-6 pm was analyzed for site impacts. PROJECTED TRAFFIC Site Traffic Trip Generation Site traffic generation was estimated by procedures recommended in the latest edition ofthe Trip Generation Manual (6th Ed) published by the Institute of Transportation Engineers (ITE). Trip rates estimated in the manual are based on actual driveway traffic measurements performed on different land uses nationwide, particularly in metropolitan areas. The site trip generation was obtained by applying the trip rates from the Trip Generation Manual to the uses of the site development. Table 1 presents the summary of the Cedar Springs project trip generation. The proposed development is projected to generate an average daily traffic (ADT) of 3,266 vehicles per day (vpd), of which the peak hour traffic (PHT) is projected to be 361 vehicles per hour (vph). An additional 68 residential-single family dwelling units are already planned for the south side of the Cedar Springs development, as a separate development. An additional 150 daily trips were assumed to result from residential-single family dwelling units on future nearby streets that will stub into the Cedar Springs Development. Together this accounts for an additional 801 vpd, which represents an additional 85 vph in the peak hour. This accounts for a total volume of 4,067 vpd, which represents 446 vph in the peak hour that will utilize the G Washington Page 4 Cedar Springs TIS.doc . . Cedar Springs Traffic Impact Study . a . . . .,. .'. Trip Generation Summarv .... .' ...... .... . .' Land Use Number of Daily Trip Peak Hour Number of Number of Peak Category Units (I) Rate (2) Trip Rate (2) Daily Trips Hour Trips Residential-Single Family 180 9,57 1.01 1,723 182 Detached Housino Residential- 112 5.84 0.54 654 60 CondominiumlT ownhouse General Office 62.4 11.01 1.49 687 93 Project Total 3,064 335 T blel Note I: Dwelling units for residential land use and 1000 Square-feet for office land use. Note 2: Institute of Transportation Engineers Trip Generation Manual, 6th Edition. Peak Hour Trip Rates for Residential Land Use are 4-6 pm Peak Hour Rates. McMillan Road/site access road intersection. Figure 3 presents the daily trips on the internal site road network. Trip Distribution Once the generated trips were estimated, they must be assigned to particular segments of the encompassing transportation network. From the project site, it was assumed that 72% of the traffic will travel to and from the east on McMillan Road, and that 28% of the traffic will travel to and from the west on McMillan Road. This split was based on the North Meridian Area Traffic Study Report. Figure 4 presents the site traffic distribution at the intersection of McMillan Road with the site access roadway. TRAFFIC ANALYSIS Site Access and Circulation A westbound left-turn lane and an eastbound right-turn lane are required on McMillan Road at the intersection with the site access road. This was determined using ACHD's warrants for right- turn bays and left-turn bays. Copies of the warrants are included in the appendix. The access to the site meets ACHD's criteria of a minimum of 440 feet driveway spacing for a full-access on Arterial Streets. All of the internal streets that are planned for front-on-housing have daily traffic projections less than 1000 vpd. The main roadway into the PUD will need to be classified as a collector and no front-on-housing is planned for this road segment, as is shown in the current site plan in Figure 2. At build-out (2007), the daily traffic on the main roadway is estimated to be a maximum of 4,067 vehicles. The COMPASS planning threshold (Level of Service C) for a two-lane collector roadway (non-business district) is 8,500 vehicles per day. Based on this criteria, the main roadway will operate well under capacity. All driveway spacing within the site must meet ACHD's minimum spacing requirements addressed in Section 7207 of the current ACHD Development Policy Manual. The currently proposed traffic-calming device (circular median) just south ofthe entrances to the office buildings and the condominiums/townhouses should be ~ PageS ~ Washington C,'"Spri,,, f1S'oe . . nW:. ~?MILLAN ROAD ~' uunu.. ~ !O ODD ~ ! ~ B D 068 292 : <> <>0</ ~ : 0 I 50, u_u_uJ RUIN T'R SC&Lto Figure 3 Internal Site Traffic ADT JUB Engineers: Cedar Spri~gS P.U.D. , " Df OCT R SP 1T ~WaShi_'''''''' 131 ~ -< 303 243. .175 0 <J: 0' 0 ~,+ <[ 0:: 0 a:: 0:: w !'-(J) Z 0 tn::::: <[ z - - 0 ...J 0:: Z w L z ,U'IlBT,A It ". bU' tl B II PP D.S LEIT ~ WaShl_;""~S 'I'oJ.ll W. CHINDEN BLVD. W. McMILLAN ROAD W. USTICK ROAD Figure 4 Site Trqffic Distribution) Peak Hour Volume JUB Engineers: Cedar Springs P.U.D. Cedar Springs Traffic Impact Study further studied to determine if it is appropriate on this collector. No concerns were identified with the preliminary site layout. . . Capacity Analysis and Leve/-of-Service A capacity analysis was performed using the latest edition of Highway Capacity Software (HCS 4.1 b) based on the 2000 edition of Highway Capacity Manual. A capacity analysis for the McMillan Road/site access road intersection for the 2007 build-out scenario was performed. The site access is proposed to be controlled by a stop sign on the south leg of the T -intersection with McMillan Road. The capacity analysis assumed a separate left- turn bay and a separate right-turn bay on McMillan Road at the intersection, based on ACHD's policy. The intersection is projected to operate under capacity for the build year of 2007. The westbound left-turn movement is projected to operate at LOS A (8.6 seconds of delay). The northbound left-turn movement is projected to operate at LOS C (20.5 seconds of delay). The northbound right-turn movement is projected to operate at LOS A (9.7 seconds of delay). Overall, the northbound movements are projected to operate at LOS B. Detailed results of the capacity analysis are included in the Appendix. The peak hour traffic signal warrant was checked for the McMillan Road/site access road intersection for the 2007 build-out year. This intersection does not comply with the peak hour traffic signal warrant based on these traffic projections. CONCLUSIONS/RECOMMENDATIONS The following are the principal findings and recommendations of the study: 1. The proposed development is projected to generate an ADT of 3,064 vpd, of which the peak hour traffic (PHT) is 335 vph. 2. The forecasted daily traffic volume for the main roadway in the PUD is only 4,067 vehicles. The planning threshold (LOS C) for a two-lane collector roadway is 8,500 vehicles. This indicates that the main roadway should provide excellent operating conditions under build-out traffic volumes. 3. All of the internal streets that are planned for front-on-housing have daily traffic projections less than 1000 vpd. 4. A separate left-turn lane and a separate right-turn lane are required on McMillan Road at the intersection with the site access road. This was determined using ACHD's warrants for right-turn bays and left-turn bays. 5. The site access is proposed to be controlled by a stop sign on the south leg of the T- intersection with McMillan Road. The intersection is projected to operate under capacity for the build year of2007. G Washington Page 8 Cedar Springs TlS,doc . . Cedar Springs Traffic Impact Study REFERENCES "Trip Generation 6th Edition," by Institute of Transportation Engineers, Washington D.C., 1997. "Highway Capacity Manual, 2000," Transportation Research Board, Washington D.C., 2000. "Development Policy Manual," Ada County Highway District, July 1994. G Washington Page 9 Cedar Springs TIS.doc . . Cedar Springs Traffic Impact Study APPENDIX G Washington Cedar Springs TIS.doc . . LEFT-TURN DECELERHION-LANE WARRANTS 30-35 mph ~ May be " required ~ '" 400 ~ 'Vi ~ " "- 300 " .2 " " ~ cOO '" > ~ 'Jot reqUlred 3 100 " <( 0 I 0 10 IS :W 25 30 ~ " 300 "Ie .::;:; ~ ~tay be ;!. req u ired :00 - " ~ -:; . 100 > ;::: :':Ot required - oL ~ <( 0 10 15 cO :5 30 DHV or J',<CJge peak-hour volume o( vehicles n":,iltng left into the J.c~ess Figure 10 72-F I 0 . . WARRANTS FOR RIGHT-TURN TREATMENTS (45-50 mph) Right-Turn Treatments (4/5 lanes) Posled Speed 45-50 mph I o I o 5000 10000 15000 20000 25000 30000 35000 Projected Volume on Major Street Right Turn Treatments (2/3 lanes) Posted Speed 45-50 mph '4jl~,)'.:f.i'" w.:::::.llJJ~;,.8.~~ "':,1. .".~ . .' . I 35000 o 5000 Radius - Taper Turn Lane Radius - Taper - Turn Lane Figure'11 72-F11 (3) Two-Way Stop Control . . Page I TWO-WAY STOP CONTROL SUMMARY General Information Site Information "nalyst Joseph Tate Intersection McMillan Rd./Site Access Rd A,qencvICo. WIS Jurisdiction Ada County Date Performed 10.12/0.2 "nalysis Time Period PM Peak Hour ~nalvsis Year 20.0.7 Project 10 Site Access Rd, EastlWest Street: Mc Mj{{an Rd. North/South Street: Site Access Rd Intersection Orientation: East-West Study Period Ihrs): 0..25 Vehicle Volumes and Adjustments Major Street Eastbou nd Westbound Movement 1 2 3 4 5 6 L T R L T R Volume 0. 131 243 175 30.3 0. Peak-Hour Factor, PHF 0.95 0..95 0..95 0..95 0..95 0.,95 Hourly Flow Rate, HFR 0 137 255 184 318 0 Percent Heavy Vehicles 0. -- - 0 -- -- Median Type Undivided RT Channelized 0 0 Lanes 0. 1 1 1 1 0. Configuration T R L T Upstream Signal 0. 0. Minor Street Northbound Southbound Movement 7 8 9 10 11 12 L T R L T R Volume 57 0. 146 0 0. 0. Peak-Hour Factor, PHF 0,95 0.95 0.,95 0..95 0..95 0.,95 Hourly Flow Rate, HFR 60. 0. 153 0. 0. 0. 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 1 0. 1 0. 0. 0. Configuration L R Delav, Queue Lenllth, and Level of Service A,pproach EB WB Northbound Southbound Movement 1 4 7 8 9 10 11 12 Lane Configuration L L R (vph) 184 60. 153 C (m) (vph) 1178 292 917 dfc 0..16 0..21 0.,17 95% queue length 0,55 0.76 0.60. Control Deiay 8.6 20..5 9.7 LOS A C A A,pproach Deiay -- - 12.7 A,pproach LOS - - B Copyright to 2000 University of Florida., All Rights Reserved Version4.1 file ://C:\ TEMP\u2k20.tmp 10/2/02