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HomeMy WebLinkAboutSILVERBERG PUD PRELIMINARY - 12 92A - SUBMITTAL DOCUMENTS - ROUND 2 - TRAFFIC STUDYSILVERBERG PUD SITE ACCESS STUDY FORT COLLINS, COLORADO NOVEMBER 1996 Prepared for: Gefroh Hattman, Architects/Planners 145 West Swallow Road Fort Collins, CO 80525 Prepared by: MATTHEW J. DELICH, P.E. 2272 Glen Haven Drive Loveland, CO 80538 Phone: 970-669-2061 FAX: 970-669-5034 a m 0 N a � a 2 PROSPECTtn S 5% N U� � LU O IL/ ` a � z �� ( Site ♦1oir SITE TRAFFIC DISTRIBUTION Figure 4 a development similar in size and character to the Silverberg project was assumed in the long range future. Under long range conditions, development activity was also assumed to the south of the site.. Various phases of the Interstate Land proposal were included in the development of background traffic. Total Traffic The site generated traffic was combined with the background traffic to determine the total forecasted traffic for the study area. Near short range (1997), site generated and total traffic volumes are shown on Figures 5 and 6. Site generated and total peak hour traffic for the year 2000 is illustrated in Figures 7 and 8, while the year 2015 is illustrated in Figures 9 and 10. As shown, these traffic projections reflect the anticipated changes in site access and adjacent/nearby development activity. VI. TRANSPORTATION IMPACTS Signal warrant, geometric, and operational analyses of the key intersections were conducted using the short range and long range traffic forecasts shown in Figures 5 through 10. Signal Warrants Using the short range peak hour traffic forecasts, it is expected that traffic signals will be warranted at the Prospect/ Northbound I-25 Ramp intersection. Using the long range peak hour traffic forecasts, it is expected that traffic signals will also be warranted at the Prospect/Southbound I-25 Ramp intersection and the Prospect/ Frontage Road intersection. Geometries Using the 1997 traffic forecasts, the short range geometry improvements were determined. Based upon the forecasted traffic volumes, an eastbound right -turn deceleration lane is needed at the site access to Prospect, according to the State Highway Access Code (SHAC). This lane should be 235 feet long. Short range (year 2000). conditions were reviewed using the traffic projections shown on Figures 7 and 8. Under these traffic loadings, the existing roadway geometry should be supplemented by a westbound right -turn deceleration lane. This assumes development 4 m $ 13 coa 9 � �o 20/575 0/135 30/45 15/35PROSPECT � 5/5-075 15 - Os 0/250 90 0/110 N , 70r0 W co_ O W = �' z Site ) SITE / TOTAL — Rounded to the Nearest 5 Vehicles. 5 5 —' NOM. 45 - NOM./25 ra �O N 0/NOM. NOM./110 0/NOM. YEAR 1997 MORNING PEAK HOUR TRAFFIC Figure 5 .1 m� �? N o� f 20/430 r— 35/55 355 f - 490 L0 N 0/170 50/175 -+- o W F- ^� o a • - CO) ai a 2� w � Z SITE / TOTAL Rounded to the Nearest 5 Vehicles YEAR 1997 AFTERNOON PEAK HOUR TRAFFIC 0/90 PROSPECT Ir 5/s 85/85 —� 1 1 m Site ) i oao 0/5 O NONOM. /rl 11 0/NM. NOM./1 5 NON./10 -� Z o Q� zo w �c� �o =o oir Figure 6 I 0 g 0 PROSPECT 04' f 50/77005 o 0 0 0/125 60 85/105 135/ 1 f-- 40/40 �135 21 �335 — )/370 � 0/205 --� 7 � 0/20 N 130/220 — 0/95 — v, o W o 0 210/210 -� � � m z �� Site SITE / TOTAL `� — Ole Rounded to the Nearest 5 Vehicles. N LO O/NOM w o o —10 115 f + [*.,I /— 0 NOM 20/25 -1 f 10/75 10/40 0 tu c� 2p o� YEAR 2000 MORNING PEAK HOUR TRAFFIC Figure 7 4 7 N /75/110 co PROSPECT n�0/10 m0/5 0/650 � o 0 0 �- 0/125 0 o r-10/105 f 115/225 105 + 35/35 + 0 NOM. 450/ 0 LO 0/290 - 7 r 0/25 -f } 15/25 --� i } 0 665 CV 120/250 --�- 0 0 135 — o Ln 10 125 n l!1 200/200 - 4 q z 10/35 o z a co 00 ii Z Site ZO SITE / TOTAL — Rounded to the Nearest 5 Vehicles. YEAR 2000 AFTERNOON PEAK HOUR TRAFFIC Figure 8 e-czl/i-85/295 �p 0/945 /450 — 0/445 7 1p 0/250 04 130/480 - F- Q W z , SITE / TOTAL Rounded to the Nearest 5 Vehicles. N In O 0 / 15 O PROSPECT ONO 0/15 f 0/525 �10/20 �215 a1s 0/210 -�- 20/190 � } 210/210 -� I 0 10/395 --� in o 0 NOM./35 n O �7 u�-i�� fizz V 0 / � Site 0 Access - 4 / 1f215 255 10 20� o 00 YEAR 2015 MORNING PEAK HOUR TRAFFIC Figure 9 A& //-755/ N 0/25 05 0 6135/525 PROSPECT-10800810 + r-10%20 450y /815 U) 0/370 -� 7 r 200/200 I 15/220 )an CV 120/575 --�- p Ln 10/620O o 0LU NOM./45�NO O OLU 7w =� /�LL eZ �� Site J , / Access SITE / TOTAL . 1ao 230 f Rounded to the Nearest 10�0� 0 5 Vehicles. o ^o YEAR 2015 AFTERNOON PEAK HOUR TRAFFIC Figure 10 activity on the north side of Prospect, which can be better addressed when more definitive development plans are put forth. Right -turn acceleration lanes are not needed, given the 35 mph posted speed limit. However, a westbound left -turn deceleration lane is warranted at the site access to Prospect. The westbound left -turn deceleration lane.should be 310 feet long, including 35 feet of storage. This distance may require slight adjustments given the spacing of the access and the Frontage Road. Since the left -turn movement will be eliminated in the future, minor adjustments are considered to be reasonable. Figure.11 reflects the anticipated long range geometry. It is expected that Prospect Road will have an arterial cross section west. of I-25 by/before the year 2015. East of the southbound ramps, Prospect Road should have one lane in each direction with the turn lanes indicated. On the Frontage Road, a three lane cross section (one lane in each direction with a shared center lane) is anticipated. Long range traffic volume projections, as shown on Figures 9 and 10, were used to assess the need for auxiliary lanes. By/before the long range future, site access will be limited to right-in/right-out on Prospect Road with a shared full movement access to the Frontage Road. Long range conditions indicate a need for maintaining an eastbound right -turn deceleration lane at the Prospect access and providing right- and left -turn deceleration lanes at the Frontage Road shared access. Design specifics at the Frontage Road access can be more accurately estimated when actual development proposals are put forth for the property to the south of the Silverberg PUD. Operation Table 3 shows the peak hour operation at the key intersections for 1997 traffic conditions. With the motel and gas/convenience store fully developed, all of the key intersections will operate at acceptable levels of service with the exception of the northbound left turn at the Prospect/Northbound I-25 Ramp intersection. This peak hour movement represents traffic entering Fort Collins and is not Silverberg related. Calculation forms are provided in Appendix C. Table 4 shows the peak hour operation at the key intersections for the short range (year 2000) traffic conditions. Calculation forms are: provided in Appendix D. As indicated, each of the study intersections is expected to operate at acceptable levels of service. However, traffic signals may be warranted at the Prospect/I-25 Off Ramp intersections to achieve acceptable levels of service. This assumes that the anticipated intensity of development occurs and background traffic volumes grow as indicated in the short range future (year 2000). M N 0 0 4 N 01 �W JUL PROSPECT N W ao a Right —in / W f— Right —out 70� W = • / / `• ` 2 Z Site �10 CC ♦ / Access kcc Shared access between Silverberg property and property to the south. LONG RANGE GEOMETRICS Figure 11 Table 3 1997 Peak Hour Operation Level of Service Intersection AM PM Prospect/I-25 NB ramps (stop sign) NB LT F F NB RT A A EB LT A A Prospect/I-25 SB ramps (stop sign) SB LT C D SB RT B B WB LT A B Prospect/Frontage (stop sign) NB LT/T/R.T A A SB LT/T/RT A A EB LT A A WB LT A A Prospect/Site Access (stop sign) NB LT B B Table 4 Short Range (2000) Traffic Peak Hour Operation Level of Service Intersection AM PM Prospect/I-25 NB ramps (stop sign) NB LT F F NB RT A A EB LT A A Prospect/I-25 NB ramps (signal) B B Prospect/I-25 SB ramps (stop sign) SB LT. F F SB RT C C WB LT A A Prospect/I-.25 SB ramps (signal) B C Prospect/Frontage Road (stop sign) NB LT/T/RT A B SB LT/T/RT A A EB LT A A WB LT A A Prospect/Site Access (stop sign) NB LT/T/RT B B SB LT/T/RT A A EB LT A A WB LT A A Table 5 Long Range (2015) Traffic Peak Hour Operation Level of Service Intersection AM PM Prospect/I-25 NB ramps (signal) C D Prospect/I-25 SB ramps (signal) B C Prospect/Frontage Road (signal) B B Prospect/Site Access (stop sign) NB RT B B SB RT C C Frontage Road/Site Access (stop sign) EB LT B B EB RT A A NB LT A A P I. INTRODUCTION This traffic impact analysis for the Silverberg PUD addresses the capacity, geometric, and traffic control requirements related to the proposed development. The Silverberg PUD is located east of Interstate 25 and south of Prospect Road in Fort Collins, Colorado. The location of the Silverberg PUD is shown in Figure 1. This study conforms to a typical traffic impact study format. The study involved the collection of data, a review of previous developments and studies in the area, trip generation, trip distribution, trip assignment, and the operation analyses of the key intersections in the area. The operations analyses were performed for the existing conditions, the opening of the convenience/gas store and one motel (1997), the short range future (2000) representing build out of the Silverberg site, and the long range future (2015). II. EXISTING AND PROPOSED CONDITIONS Existing and Proposed Uses The land for this development is currently vacant. The area is in transition from a rural to urban environment. Figure 2 shows the concept plan for the Silverberg PUD. As shown, the Silverberg PUD development is proposed as a mixed -use project, consisting of the following land use elements: motel, fast food and sit-down restaurants, and a convenience store with gas. For analysis purposes, the Silverberg PUD was divided into two phases. It.was assumed that Phase I would provide the convenience/gas store and 66 motel rooms and would be built out by 1997. The balance of the development is assumed to be build out by the year 2000. Site Access Access to the site is proposed via a full turn movement access from Prospect Road in the short range future. No additional access to the site is proposed at this time. In the long range future, direct access to the Frontage Road is expected when the property to the south is developed. Since the Silverberg project does not abut the Frontage Road, the timing and availability of a Frontage Road access cannot be predicted. For analysis purposes, however, a shared access (with the property to the south) was assumed in the long range future. In concert with Frontage Road access, it was further assumed that the Prospect .Road intersection would be 1 Long range operation was assessed using traffic volumes and roadway geometry anticipated in 2015. Under these conditions, traffic signals are assumed at both I-25 ramps and the Prospect/ Frontage Road intersections. Operating conditions in the long range future are shown on Table 5. As shown, all movements are expected to operate acceptably in the long range future. Calculation forms are presented in Appendix E. VII. RECOMMENDATIONS This study assessed the transportation impacts associated with the development of the Silverberg PUD, located east of I-25 and south of Prospect Road in Fort Collins, Colorado. At the proposed development level, it is expected to generated 6640 trip ends on an average weekday. The potential impacts of the proposed project were evaluated at the following intersections: Prospect Road/I-25 Northbound Ramps, Prospect Road/I-25 Southbound Ramps, Prospect Road/Frontage Road, and all accesses to Prospect Road and the Frontage Road. Currently, the key intersections analyzed as part of this study operate acceptably with their existing control and geometry. In the 1997 evaluation year with a motel and gas/convenience store fully developed, all intersections are expected to operate acceptably with the exception of the northbound ramp left turn to westbound Prospect Road. This movement is not site related and is expected to operate at level of service F during the peak hours. Given the limited duration of level of service F operation, it is considered acceptable/normal. At the Prospect/site access intersection, conditions indicate the need for an eastbound right - turn deceleration lane for site traffic. In the short range (year 2000) future, signals will likely be warranted at the Prospect/Northbound Ramps and Prospect/Southbound Ramps intersections. The minor street left -turn movements at these intersections are expected to operate at level of service F during both peak hour periods with stop sign control. If traffic volume projections are realized, traffic signals should be considered at that time. Level of service C or better can be expected with traffic signal control. At the Prospect/site access intersection, short range (year 2000) conditions indicate the need for a westbound left -turn deceleration lane for site traffic. This lane will be warranted in conjunction with build out of the Silverberg PUD. In the long range (year 2015) future, traffic signals are expected to bewarranted at the Prospect/Frontage Road intersection. Access modifications are also expected to occur. These 6 t tmodifications involve limiting the Prospect Road access point to right -turn movements and providing additional site access to the ' Frontage Road via a shared access with the property to the south. The shared access will provide a full -turn access to the Frontage Road. In conjunction with the Frontage Road access, a southbound right -turn lane and a northbound left -turn lane are anticipated. ' The design parameters for these auxiliary lanes can be better predicted when development proposals for the area to the south of Silverberg PUD materialize. Based on the assumed developments surrounding the site and the assumed future roadway geometry, acceptable long range operating conditions can be expected. Long range geometry is shown in Figure 11. 7 I 4 N �. Golf Course II 81 ; u it Giddings "II \\ ri a It II'• � \�-= I __--_ II III 'II �p )� _. 'P , •. tt���\\per nI. •�II .(/��_ ii mil\ ;+irr ; ILIL l {it j�>, .4995 ` a . , MiSubsta <9 J II - � II _ _ _ .. _.. ._.._ Y11 j II _ __ _________ _ 4 if 1' auar North Yards _ COLORADO. • :Black Hollow Reiin ry _ Junction « <060 �I COL 05 JJ Downtown Sinnard G �� '• �,• I \'��Fort Collins t • ! ORA00 ;ANC �—i�•� �� \Airpark �7 Gravel Pit .:�'.�: Roselawn ?��❑© .,..BoS age :=i=`C�';- ` �� Cem _ D' •>.•. '. :> nFIFDisposal, ;>,. • vhead At•ro\ "v rs,o7 1. rsos 954 SM4Pr n� J :... n t1U p NN CGravel P- � �I n I 0 K Q it 'OSPECT Rb*. % It Or EH0E ='�;i„ I �, U= •�`�� \�I,o o Towers ii 1 �� heatf` ,000��UN 20 C� (.lU� I it r___.. ^' 41 _ , TiILI mr rya ��(i ;; SILVERBERG PUD U ' II• �� • SM4874 o s rl ,4a6 5 � IL q m gar ' � 1��� n .. - - — � • _ .. � I `a\\_� —._ =; R•" \t _\_ it �. ( ,/, �i1 \ rr{{JJR NO SCALE SITE LOCATION Figure- 1 I 4 z \ NO SCALE I Motel a 1 � w SITE ACCESS 0.; 6 in I� �LL- a I = 3 o v o � ft-. I V) I I Pumps C- \ STORE - INTERSTATE 25 CONCEPT PLAN Figure 2 limited to right -turn movements when alternative access became available. Prospect Road is a two lane, east/west street with a rural cross section within the study area. Access to/from I-25 is provided at Prospect Road. The northbound and southbound I-25 ramps at Prospect Road are stop -controlled for the ramps. Prospect Road has a posted speed limit of 35 mph in this area. The Frontage Road is also a two lane roadway with a posted 35 mph speed limit. The Frontage Road has an advisory speed of 30 mph. Existing Land Uses The adjacent land uses near the Silverberg property are as follows: 1) to the west is Interstate 25 with an interchange at Prospect Road; 2) to the north across Prospect Road is vacant land; 3) to the east is the East Frontage Road of I-25 and largely agricultural land east of the Frontage Road; and 4) to the south is agricultural land and some commercial/industrial uses along the Frontage Road. The topography in the area is essentially flat in the immediate area of the Silverberg PUD, except for the embankment of the I-25/Prospect interchange. Existing Traffic The existing peak hour traffic counts at the key intersections in the area are shown in Figure 3. Peak hour traffic data was collected at the three study intersections in either 1995 or March, 1996. Raw traffic counts are provided in Appendix A. Existing Operation The existing peak hour operation at the key intersections is shown in Table 1. Calculation forms for these analyses are provided in Appendix B. The intersections were analyzed using the unsignalized intersection techniques from the 1994 Highway Capacity Manual (1994 HCM). As shown in Table 1, each of the study intersections is currently operating at acceptable levels of service. Acceptable operation is defined as level of service (LOS) D or better. III. TRIP GENERATION Trip generation is important in considering the impact of a development on the existing and proposed street system. Trip Generation, 5th Edition, ITE and the February 1995 Update to this publication were used to forecast trips that would be generated by 4 I � f 540/393 /22 9/12 25 f 150/272 ; 235/473 58 N 61/125 H Wco Cv Q F- � y W Q =� z AM/PM ADJUSTED TO REFLECT 1996 TRAFFIC COUNTS AND BALANCED TRAFFIC VOLUMES. PROSPECT Site `I N I1 �-0/3 1 47 /- 2/1 1/12 46 11r. Lo 25/16 W C7 Zo c cc k EXISTING PEAK HOUR TRAFFIC Figure 3 Table 1 Existing Peak Hour Operation Intersection Prospect/I-25 NB ramps (stop sign) NB LT NB RT EB LT Prospect/I-25 SB ramps (stop sign) SB LT SB RT WB LT Prospect/Frontage (stop sign) NB LT/T/RT SB LT/T/RT EB LT WB LT Level of Service AM PM D D A A A A C C B A A A A A A A A A A A the proposed Silverberg PUD development. A trip is defined as a one way vehicle movement from origin to destination. The Regional Transportation Plan for the North Front Range Area has goals aimed at reducing single -occupant vehicles. However, for a conservative analysis, no trip reductions were assumed as part of this traffic study. Trip generation for Silverberg PUD is shown in Table 2. As shown, the first phase of the Silverberg development (a motel with 66 rooms and a gas/convenience store with 12 pumps) is expected to produce 152 morning peak hour trips, 178 afternoon peak hour trips, and 2160 daily trips. Under build out conditions, the site generated traffic is expected to be 500 morning peak hour trips, 443 afternoon peak hour trips, and 664 daily trips. IV. TRIP DISTRIBUTION Trip distribution for the Silverberg PUD was based on existing/future travel patterns, land uses in the area, and consideration of trip attractions/productions in the area. The existing roadways in the area also play a role in developing the trip distribution. Virtually all uses within the project are oriented to the west, either to Fort Collins or toward I-25. Primary emphasis, however, is expected to be toward I-25. Trip distributions are shown in Figure 4. V. TRAFFIC FORECASTS Trip Assignment The trip assignment is how the generated and distributed trips are expected to be loaded on the roadway network: This is a function of site access point(s) and the existing and planned street system. Background Traffic Background traffic was determined for the 1997 time frame associated with the initial phase of development, and the short and long range future years. The background traffic for the area streets was developed using the existing traffic counts performed at the study intersections. A review of historical traffic count data, projections from the "North Front Range Regional Transportation Plan" (NFRRTP), and other traffic studies in the area of the site was conducted to determine future traffic. This growth generally includes traffic that will be generated in the immediate area of the site. In this instance, a small development north of Prospect Road was assumed in the short range future and 3 Table 2 Trip Generation Daily A.M. Peak P.M. Peak Land Use Trips Trips Trips Trips Trips in out in out PHASE I (1997) Motel - 66 Rooms 410 8 14 16 14 Gas/C-store - 12 pumps 1750 66 64 74 74 Subtotal 2160 74 78 90 88 Phase II (2000 Fast Food Restaurant 2840 114 110 76 70 4.0 KSF Motel - 66 Rooms 410 8 14 16 14 Sit -Down Restaurants (2) 1230 52 50 50 39 3.6 KSF and 3.3 KSF Subtotal 44B0 174 174 142 123 TOTAL 6640 248 252 232 211