Loading...
Traffic Impact StudyCavanaugh Ridg Meridian, ID i or tfil A T August 17, 2009 Thompson Engineers Traffic and CivilAk Inc. 181 East 50th St Garden City, ID 83714 (208)853-4410 Thompson Engineers Updated Traffic Impact Study Traffic and civil Inc. Cavanaugh fridge, Meridian, Idaho Thompson Engineers, Inc. has been retained to update the traffic EXECUTIVE impact study for the proposed Reflection Ridge development dated August 15, 2005. The primary purpose of the update is to revise SUMMARY calculations using current traffic counts. The project is now called Cavanaugh Ridge and is located near Meridian, Idaho. The proposed development is an 89.7 acre development consisting of detached single family residences. The site plan is slightly revised from the original proposed site plan and is shown in Figure 2. The preliminary plan indicates the development will consist of 252 Single Family Dwellings, which is a decrease from 259 single family dwellings. There will be varying sizes of lots and value of the homes. The area of influence is anticipated to be Ada County south of the City of Meridian, Idaho. The primary impact will be along Locust Grove and will. include the intersections of Locust Grove and Victory, and Locust Grove and Amity. The following are the principal findings and recommendations of the study: IF The proposed development is projected to generate an average daily traffic of 2412 new vehicle trips per day, of which 189 will occur during the AM peak hour and 255 will occur during the PM peak hour. ® The proposed development will access the transportation system primarily through Locust Grove Road. Future development will create other opportunities to access the transportation system to the west and south, 19 During the PM Peak Hour, the intersection of Victory Road and Locust Grove Road currently operates at level of service F under existing traffic conditions. Additional lanes are required to improve the intersection to an acceptable level of service. E During the PM Peak Hour, the intersection of Victory Road and Locust Grove Road will operate at level of service F under background traffic conditions. Additional lanes are required to improve the intersection to an acceptable level of service. With additional lanes, the intersection will operate at L©S D. With the addition of site traffic to the intersection of Victory Road and Locust Grove Road, the intersection will further deteriorate. With additional lanes, the intersection will operate at LOS D with site traffic. If the intersection is not improved, site traffic will likely seek alternative routes to and from the site. During the PM Peak Hour, the intersection of Amity Road and Locust Grove Road will operate at level of service C under 2014 background traffic conditions. With the site traffic, the intersection will operate at level of service D. IF During the PM Peak Hour, the intersection of W. Wrightwood Drive and Locust Grove Road will operate at level of service C under 2014 Total traffic conditions. A right turn lane is warranted on Locust Grove. Thompson Engineers Updated Traffic Impact Study rrnft and ctdj Inc. Cavanaugh Ridge, Meridian, ID N Locust Grove, Victory Road and Amity Road have the capacity to absorb the site generated traffic based on the current traffic counts. Under 2014 background conditions, neither Victory Road nor Amity Road will exceed the level of service C planning thresholds established by COMPASS. . K Traffic will not exceed 1,000 vehicles per day on any internal streets except east of the traffic circle. This segment should be classified as a collector. All other streets should be classified as local streets. T.\projecisW9-)3 trfrdly UanAd*rslCR TIS.doc Page 2 of 16 Thompson Engineers Updated Traffic ftnpact Study Trsti9c and Clvl! Inc. Cavanaugh Ridge, Meridian, ID -- Thompson Engineers, Inc. has been retained to update the traffic INTRODUCTION impact study for the proposed Reflection Ridge development dated August 15, 2005. The primary purpose of the update is to revise calculations using current traffic counts. The project is now called Cavanaugh Ridge and is located in Meridian, Idaho. The project is located south I-84 and between SH-69 and Eagle Road, approximately as shown in Figure 1. The purpose of this study is to evaluate the anticipated traffic impacts resulting from the project and male recommendations for mitigation of the impacts. In particular, the scope of the study includes the following: ff Trip Generation of the proposed development 1B Trip distribution and traffic assignment of the site generated traffic It The capacity of the transportation system to support the development. If Intersection treatment of the site access points. Figure 1 Proiect Location LQ ..;"�._. y . 34 J,>._� ....7 1 f r -1 fL Gs Project Location Copy6ght@2004Wrd oft Co . !%nd'ar its su tirfrl. AI ri hts r*seruL%d. T.'\iJ•ajeC1A09-13 afjlsity' Gank'Voc SCR TI .eloc Page 3 of 16 Thompson Engineers Updated Traffic Impact Study Traffic and cNu mc. Cavanaugh Ridge, Meridian, ID The proposed development is an 89.7 acre development consisting of PROPOSED detached single family residences. The site plan is slightly revised DEVELOPMENT from the original proposed site plan and is shown in Figure 2. The preliminary plan indicates the development will consist of 252 Single Family Dwellings, which is a decrease from 259 single family dwellings. There will be varying sizes of lots and value of the homes. The primary access to the transportation system will occur at on Locust Grove. A secondary access point will be available vial Rumpel Lane to the west. Additional access points will be available in the future as development occurs and connects to the internal roadways of the project. Study Area STUDY E The area of influence is anticipated to be Ada County south of the City CONDITIONS of Meridian., Idaho. The primary impact will be along Locust Grove and will include the intersections of Locust Grove and Victory, and Locust Grove and Amity. Land Use The site is currently zoned as R4. The City of Meridian Comprehensive Plan Future Land Use Map, adopted in 2002 and amended in 2008, identifies this area as primarily medium density residential, with low density to the north, and both medium and high density residential and neighborhood commercial to the south. EXISTING Traffic Volumes CONDITIONS Existing traffic information was obtained from a traffic counts during the week of August 10, 2009, The PM Peak hour traffic counts are shown in Figure 3. Traffic volumes have changed significantly since the original report and traffic counts. This is primarily due to the completion of the Locust Grove over pass over Interstate 84. Prior to this overpass, Locust Grove Road was a dead end north of Overland Road. Average daily traffic (ADT), design hour volume (DHV), directional split information was obtained from the ACHD web site. A copy of the report is included in the appendix of this report. Based on this report, the ADT Locust Grove north of Amity Road on September 25, 2008 is 3,330 vpd. The ADT on Victory Road is 5,819 vpd east of SH69 on June 11, 2009. The ADT on Amity Road is 5,701 vpd west of Eagle Road from September 25, 2008. T.•lpro*"s109-1.3 aff"I ty ballk-WncACR TIS dac Page 4 of 16 Thompson Engineers Updated Traffic Impact Study Traffic and CMI Cavanaugh Ridge, Meridian, ID Plan it' oj ii w; [w I M1 R - Ro -.0 R Ilia, Be! SO Oft 4a, I 1,, 11 il.11111 , 4 W'.4am-fa- TAPrOjeCIA09-13 affinity bank-Woc,\CR TIS.doc Page 5 of 16 Thompson Engineers Updated Traffic Impact Study Traffic and CMI"4k- Inc. Cavanaugh Ridqe, Meridian, ID lure 3 Existing PM Peak Hour Conditions tit. . . ..... ......... ......... ........ ....................... .... . .. . .. ..... - . ... ... - ................ . ... . ...... . . . ................ . ..... . . ........... 71 329 48 C 47 =0 79 120 E* 253 41 58 <zo a:> 23 181 23 I 64 100 37 129 3 5 63 60 25 <= 313 1 67* 4 T"P-Ojecls\09-13 rjffhwy b,,,A,\,I,,,\CR TIS.doc Rige 6 of 16 Thompson Engineers Updated Traffic Impact Study Traffic and Civil'4- Inc.- Cavanaugh Ridge, Meridian, 1D Road System In the vicinity of the project, Locust Grove is a two lane rural highway with limited shoulders, and no curb, gutter or sidewalk, The posted speed limit is 50 mph. It is classified by COMPASS as a minor arterial roadway. Access is mostly unrestricted. Near the intersection with Locust Grove, Victory Road is a two lane rural highway with limited shoulders, and no curb, gutter or sidewalk. The posted speed limit is 45 mph. It is classified by COMPASS as a minor arterial roadway. Access is mostly unrestricted. At the intersection, there are no turn lanes. Near the intersection with Locust Grove, Amity Road is a two lane rural highway with limited shoulders, and no curb, gutter or sidewalk. The posted speed limit is 50 mph. It is classified by COMPASS as a minor arterial roadway. Access is mostly unrestricted. At the intersection, there are no turn lanes. System Improvements At this time, there are no proposed roadway construction projects scheduled by either ACHD to widen Locust Grove Road, Victory Road, or Amity Road that will increase the capacity of the transportation system in the vicinity of the project. Other developments will likely connect to the project roadway system and allow other connection points to the transportation system. However, no such improvements are planned at this time, so they are not included in this study. STUDY PERIOD Build Out Year The Build Out Year for this project is assumed to be 2014, based on conversations with the developer. PROJECTED Background Traffic TRAFFIC Future traffic is obtained by expanding the existing traffic volumes by a growth factor. For the build out year, a growth factor of 4% per year is used based on the traffic projections provided by COMPASS and per discussions with ACHD. The Bellingham subdivision is currently proposed for this area. Traffic estimated to be generated by this development, based on the distribution in the Bellingham Traffic Impact Study prepared by Washington Group International, is added to the background traffic. Traffic from other subdivisions currently under construction are assumed to be included in the 10% growth rate. PM Background traffic volumes for 2009 are shown in Figures 4. T.WOJ'ctsVl9-13 affinity hand-dacs\CR TI.S.do, Page 7 of 16 Thompson Engineers Updated Traffic impact Study Traffic and CMI,4k- Inc. Cavanaugh Ridge, Meridian, ID Ficsure 4 Background Traffic 2014 PM Peak Hour --Jl L -! U 86 435 (58 1 57 �6 162 308 --- 101 33 237 � 39 73 411:1 30 381 chi 5 T.•Wr0jectsl09-13 n,1firuty bairk\d,,,\CR TIS.rloc Page 8 of 16 Thompson Engineers updated Traffic Impact Study rmm . Inc. Cavanaugh Ridge, Meridian, Ill Trip Generation Site trip generation is estimated using the procedures recommended in the latest edition of the Trip Generation Manual (71h edition). Published by the Institute of Transportation Engineers, in the absence of site -specific data. The site trip generation is obtained by applying the trips generation rates obtained from the Manual for each category of land use within the development. Table 1 shows the average daily trip generation of the site. As shown below, the site is estimated to generate 2,412 trips per day. No reduction is made for trip capture, pass by, or modal split. As shown in Table 1, 255 of the trips occur in the PM peak hour. 189 of the trips occur during the AM peak hour. Since this volume is Lower than the PM peak bout-, the analysis will be limited to the PM peak hour. Table 1 Summary of Trip Generation Calculation Cavanaugh Ridge Summary of Trip Generation For 252 Dwelling Units of August 14, 2009 Calculation Single Family Detached Housing Average Standard Rate Deviation Adjustment Factor Driveway Volume Avg, Weekday 2-Way Volume 9.57 3.69 1.00 2412 7-9 AM Peak Hour Enter 7-9 AM Peak Hour Exit 7-9 AM Peak Hour Total 0.19 0.56 0.75 0.00 0.00 0.90 1.00 1.00 1.00 4 141 189 4-6 PM Peak Hour Enter 4-6 PM Peak Hour Exit 4-6 PM Peak Hour Total 0.64 0.37 1.01 0.00 0.00 1.05 1.00 1.00 1.00 1 93 93 255 Saturday 2--Way Volume 10.10 3.68 1,00 2545 Saturday Peak Hour Enter Saturday Peak Hour Exit Saturday Peak Hour Total 0.51 0.43 0.94 0.00 0.00 0.99 1.00 1.00 1.00 129 108 237 Note: A zero indicates no data available. Source: Institute of Transportation Engineers Trip Generation, 7th Edition, 2003, TRIP GENERATION By MICROTRANS 7"P ojects\09-13 afairy 1,nnkV1oCs\CR TGS.r1oc Page 9 of 16 ThompsonEngineers Updated Traffic Impact Study Traffic and ctvrt 111c. Cavanaugh Ridge, Meridian, ID Trip Distribution hi order to determine impacts, the trips generated by the site must be distributed to destinations throughout Ada County and assigned to the transportation system. Based on current travel patterns, the modal split is negligible, so all trips are assigned to vehicles, and the vehicles are assigned to the roadway system. The distribution and assignment for this development is based on existing travel patterns as determined from COMPASS data. The distribution is shown in Figure 5. It is estimated that 75% of the traffic will travel to and from areas via Locust Grove north the site, and 25% via Locust Grove south of the site. Figure 5 Site Traffic Distribution Site traffic is distributed at each intersection in accordance with this distribution and assignment. Figures 6 shows the distribution of site generated traffic at each of the intersections on Locust Grove Road. T.'Wojccisl09-13 rrfftili ;V bank-Woc stCR T!S Bloc Page 10 of 16 Thompson Engineers Updated Traffic Impact Study Traffic and Civil Inc.i. Cavanaugh Ridge, Meridian, ID Figure 6 Site Traffic PM Peak Hour 0 58 0, 0 0 31 U! 0 a0 o 0 8 13 0 0 0 T:• projects\09-1.? nffr.ity ba"A1111s\CR T1S dnc Page 1 i of 16 Thompson Engineers Traffic and Civil lnc. Total Traffic Updated Traffic Impact Study Cavanar gh Ridge, Meridian, ID The site traffic is then added to the background traffic as determined above. Figure 7 shows the total traffic at each intersection for PM peak hour conditions for the build out year of 2009. Figure 7, Total Traffic 2014 PM Peak Hour T.'�Projecfst09-13 aff,?jiA' l mrkklocs\CR TIS doc _120 255 76 �43 0 6 )6 :MD18 41 119 33 88 127 81 4-j�,43 ? 381 �i 6 87 5 Page 12 of 16 Thompson Engineers Updated Traffic Impact Study Ti-efficand CIWI Inc. Cavanaugh Ridge, Meridian, ID TRAFFIC Capacity Analysis and Level of Service ANALYSIS Capacity analysis was performed using the Highway Capacity Software (HCS+), based on the 2000 edition of the Highway Capacity Manual. Level of service for both stop eontrolled intersections and signalized intersections are based on the average delay of vehicles traveling through the intersection. For stop -controlled intersections, the average delay incurred by the minor movements is used to determine the level of service. Copies of the calculations are included in the appendix of this report. The results are be summarized as follows: Table 2 - LOS Summary PM Peak Hour Conditions 2009 2014 Existin -Background I Total Delay LOS Delay LOS Delay LOS Amity and Locust Grove 13.4 B 20.8 C 26.1 D Victory and Locust Grove Mitigated wl left turn lanes 63.1 14.8 F B 186 21.8 F D 256 29.0 F D Wrightwood and Locust Grove 17.8 C '� Based on the planning thresholds for roadway by COMPASS, .Locust Grove Road, Amity Road and Victory Road will all have the capacity to absorb the traffic generated by the site. If we estimate a 4% growth rate in traffic volumes, by 2014 Amity and Victory will operate at Ievel of service C, with or without the traffic from the proposed development. Right-of-way should be preserved for future widening of Locust Grove. As a section Iine road, right-of-way should be preserved for a five -lane roadway. Internal Traffic Figure & shows the anticipated traffic volumes on internal roadways. Wrightwood Drive will carry enough traffic to be classified as a collector road. All other roads may be classified as local roads. The road just west of the traffic circle does incur traffic very near the 1000 vpd threshold for local roads. However, the project provides a stub road to the west, which will connect with Rumpell Lane when that area is developed_ That will provide an additional means of access to the transportation system, and will relieve the pressure on the internal road. The traffic circles do not have the volumes to require design to roundabout standards. These should be viewed as traffic calming features rather than traffic control devices. TAprojecIA09-13 «fr'PrirV 1fl"k' cCs\CR 77S.doc Page 13 of 16 Thompson Engineers Updated Traffic Impact Study rrarr,� and c ry ,� Cavanaugh Ridge, Meridian, ID T.•ysrofectsi09-J3 o0lbrity hank iocs\CR TIS.doc Page 14 of 16 Thompson Engineers Updated Traffic Impact Study TraMc end Civil ,n�_ Cavanaugh Ridge, Meridian, ID Off Site improvements A right turn lane into the site from Locust Grove is warranted. A left turn lane is not warranted based on ACHD guidelines. The intersections Amity Road and Locust Grove will function at an acceptable level of service with the addition of site traffic. No improvements are necessary to this intersection as a result of traffic generated by the project. The intersection of Victory Road and Locust Grove is currently functioning at a poor level of service. Under background traffic conditions, the level of service will deteriorate to an unacceptable level. The primary cause of the deterioration of this intersection is probably due to the shift in traffic patterns brought about with the completion of the Locust Grove overpass of I-84, This brought about a significant increase in north -south, traffic on Locust Grove. Site traffic will only increase the traffic at the intersection by 12%v of the anticipated total. To function at an acceptable level of service under background traffic conditions, additional lanes are required on all four approaches to the intersection of Locust Grove and Victory Road. All lanes should allow through movements. However, this would require the construction of accepting lanes on the down stream leg of all four approaches. Creating a separate left turn lane at all four approaches would improve the level of service and provide reasonable mitigation. Without improvements to this intersection, site traffic will probably use other roads to access the site, including additional traffic to Amity Road and Rumpel Lane. The transportation system in the vicinity of the proposed development DISCUSSIONS has capacity to absorb the traffic generated by the development, however the intersection of Victory Road and Locust Grove Road will require improvements to operate at an acceptable level of service. Adding left turn lanes on Victory Road and Locust Grove Road will provide the capacity to service this, and other development. Since this intersection has large volumes on several of the turning movements, this intersection should be considered for a round about for traffic control. Preliminary analysis indicates that this intersection would operate at acceptable v/c ratios with less delay as a single lane roundabout than with all - way stop controlled intersetions. However, this intersection may require two lanes in the near future. The site plan indicates that stub streets will be provided at three locations for connection to the roadway systems of future developments. The stub street to the west connects near Rumpel Lane, which is currently shown on the Ada County web site as a private road. If the area around Rumpel Lane develops, Rumpel Lane would become a public road and provide a direct access to SH 69 from the subdivision. This will ease traffic in the subdivision, and on Locust Grove. T-'�ProjecIA09-13 afnify haAMOCACR TIS clac Page 15 of 16 Thompson Engineers Updated Traffic Impact Study Traffic and cn•,r — Inc.� Cavanaugh Ridge, Meridian, ID This study identifies transportation impacts associated with the CONCLUSIONS proposed Cavanaugh Ridge subdivision in Meridian, Idaho. It is an update of a study from August of 2005. The project was called Reflection Ridge at that time. The site plan did not significantly change, but the traffic counts were from 2003, so an update was necessary. The following are the principal findings and recommendations of the study: The proposed development is projected to generate an average daily traffic of 2412 new vehicle trips per day, of which 189 will occur during the AM peak hour and 255 will occur during the PM peak hour. It The proposed development will access the transportation system primarily through Locust Grove Road. Future development will create other opportunities to access the transportation system to the west and south. During the PM Peak Hour, the intersection of Victory Road and Locust Grove Road currently operates at level of service F under existing traffic conditions. Additional lanes are required to improve the intersection to an acceptable level of service. During the PM Peak Hour, the intersection of Victory Road and Locust Grove Road will operate at level of service F under background traffic conditions. Additional .lanes are required to improve the intersection to an acceptable level of service. With additional lanes, the intersection will operate at LOS D. K With the addition of site traffic to the intersection of Victory e Road and Locust Grov Road, thie intersection will further deteriorate. With additional lanes, the intersection will operate at LOS D with site traffic. If the intersection is not improved, site traffic will likely seek alternative routes to and from the site. During the PM Peak Hour, the intersection of Aniity Road and Locust Grove Road will operate at level of service C under 2014 background traffic conditions. With the site traffic, the intersection will operate at level of service D. 1 During the PM Peak Hour, the intersection of W. Wrightwood Drive and Locust Grove Road will operate at level of service C under 2014 Total traffic conditions. A right turn lane is warranted on Locust Grove. Locust Grove, Victory Road and Amity Road have the capacity to absorb the site generated traffic based on the current traffic counts. Under 2014 background conditions, neither Victory Road nor Amity Road will exceed the level of service C planning thresholds established by COMPASS. . Traffic will not exceed 1,000 vehicles per day on any internal streets except east of the traffic circle. This segment should be classified as a collector. All other streets should be classified as local streets. 7}jarojee/$W9-73 arinity ba,,kV0CSX 'R TIS.doc Page 16 of 16