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HomeMy WebLinkAboutRS_Traffic_Study_190215_v1.PDF 6544 NE 61st Street Seattle, WA 98115 206-523-3939 hefftrans.com T ECHNICAL MEMORANDUM Project: Renton Excel Charter School Subject: School Traffic and Parking – Phase 1 Scoping Date: January 25, 2019 Authors: Jennifer Barnes, P.E., Associate Principal Julie Royson, Transportation Engineer This memorandum presents trip generation and parking demand estimates that are projected to result from a proposed relocation and expansion of the Excel Charter School in Kent to a new site in Renton. It is in- tended to support coordination with the City of Renton (City) staff to determine the scope of the transpor- tation impact analysis required for the project. This memorandum describes traffic and parking character- istics at the existing school, and provides estimates of the trip generation and parking demand expected with the proposed school at the new site, as well as the estimated trips that would be eliminated by the re- moval of the retail use at the new site. Questions about this analysis should be directed to Jennifer Barnes, at (206) 324-3623. 1. Project Description The existing campus of the Excel Charter School is located at 19300-108th Avenue SE in Kent; the school serves grades 7 through 10 with a current enrollment of 170 students. The bell schedule is 8:00 A.M. to 3:30 P.M. on all days except Wednesday, which has a 12:30 P.M. dismissal. There are also after- school clubs and tutoring on Monday through Thursday that generally end by 4:15 P.M. The new school would renovate an existing building located at 16950-116th Avenue SE in the Cascade Village commercial development in Renton; the proposed project location is shown on Figure 1. The new school would serve grades 6 through 12 with an enrollment capacity of 525 students. The project site has an existing surface parking lot located northeast of the building. The south portion of the lot would be re- developed as an outdoor play area. The remaining portion of the parking lot would be reconfigured to pro- vide a bus loading area, family vehicle loading area, and 60 on-site parking spaces. The family vehicle loading area would also be used to accommodate short-term and visitor parking, with capacity of 11 addi- tional parked vehicles, during periods outside the morning arrival and afternoon dismissal periods. The proposed site plan is shown on Figure 2. The project would renovate an existing 40,664 square foot (sf) building which previously housed a QFC supermarket. Although the commercial building is not currently occupied, it could reopen and resume its previous use without requiring any new permits; therefore, it is appropriate to account for the trip credit that would result from the removal of the grocery store use. RECEIVED 03/06/2019 amorganroth PLANNING DIVISION 01.25.2019 RENTON EXCEL Charter School SE 192nd St116thAve SESE 168th St SE 196th St SE Petrovitsky Rd SE 208th St 140thAve SE148thAve SESW 7th St 167 405SWGradyWy SE 200th St N Project Site Not to Scale Benson Dr S108thAve SEFigure 1 Project Location 01.25.2019 RENTON EXCEL Charter School Figure 2 Site Plan N Source: Miller HayashiArchitects, January 23, 2019 Renton Excel Charter School School Traffic and Parking – Phase 1 Scoping January 25, 2019 | 4 2. Trip Generation 2.1. Overview of Approach Trip generation estimates for school projects are typically developed using one of two methods. For new schools, rates published by the Institute of Transportation Engineers (ITE) in the Trip Generation Manual 1 are typically applied. For replacements or expansions of existing schools, it is generally preferred to use counts of traffic at the existing school. Since the proposed school would serve both middle and high school students, it would have different traf- fic characteristics than the existing school that serves only middle school students. With high school stu- dents added, it is expected that a lower proportion of total students would be dropped off and picked by family vehicle, but some students could drive and park personal vehicles. While traffic counts at the existing school cannot be directly applied to the proposed project, they were conducted to determine if the school’s existing travel characteristics more closely resemble those of a public school or a private school. Although charter schools are public schools, they tend to have larger draw areas and more limited school bus service than conventional public schools, and therefore have po- tential for trip characteristics that align more closely with private schools. It should be noted that the ex- isting school does provide yellow bus transport for students, and would continue to provide school bus service at the new site. ITE provides average trip rates for Middle School (Land Use Code [LU] 522), High School (LU 530), Private K-8 School (LU 534), and Private K-12 School (LU 536). It is noted that the current edition of the Trip Generation Manual also includes a Charter Elementary School category, but there is not a category for charter schools at the upper grade levels. To determine the appropriate rates for the new charter school in Renton, the trip generation characteristics of the existing school were determined, and then compared to the ITE public and private school rates. 2.2. Trip Characteristics of Existing School The existing school site is configured such that all trips that it generates enter and exit via two driveways. Traffic counts were conducted by Idax Data Solutions at the two school driveways on Tuesday, October 16, 2018. The morning counts were performed from 7:00 to 9:00 A.M. and the afternoon counts were per- formed from 2:45 to 4:45 P.M. The school’s existing trip rates were determined by dividing the trip total for the peak hour within each count period by the student enrollment of 170 students. Table 1 summarizes the peak hour trip generation rates derived for the school based upon the driveway counts and the school enrollment at the time of the counts. The ITE rates for Private K-8 School (LU 534) and Public Middle/Junior High School (LU 522) are shown for comparison. As shown, the rates at the existing school were most similar to the Private K-8 School rates. Although the derived afternoon rate was higher than the average rate for Private K-8 Schools, it was within the range of rates identified by ITE for that category. Based on these data, Private K-12 School (LU 536) was determined to be the ap- propriate ITE land use category to be applied to the proposed school. 1 ITE, 10th Edition, 2017. Renton Excel Charter School School Traffic and Parking – Phase 1 Scoping January 25, 2019 | 5 Table 1. Trip Generation Summary – Renton Excel Charter School Observed Trips ITE Rates (trips/student) Time Period In Out Total Observed Rates a (trips/student) Middle School (LU 522) Private K-8 (LU 534) Morning Peak Hour (7:15 – 8:15 A.M.) 86 75 161 0.95 (53% in, 47% out) 0.70 0.93 Afternoon Peak Hour (3:00 – 4:00 P.M.) 62 65 127 0.75 (49% in, 51% out) 0.35 0.62 Source: Heffron Transportation, January 2019. a. Derived by dividing the vehicle trips generated by the school during the peak hour by the school enrollment of 170 students. 2.3. Trips Generated by Proposed Project Table 2 summarizes the estimated trip generation for the proposed Renton Excel Charter school, applying the ITE Private K-12 School rates to the proposed capacity of 525 students. As shown, the school is esti- mated to generate about 1,300 daily vehicle trips, with 425 occurring in the AM peak hour when students arrive, 305 in the afternoon peak hour when the majority of students depart, and 89 in the commuter PM peak hour which is when traffic on the vicinity streets is highest. Table 2. Vehicle Trip Generation Estimate – Proposed School Vehicle Trip Estimate Time Period Trip Rate a Inbound Outbound Total Daily 2.48 trips/student (50% in, 50% out) 650 650 1,300 Morning Peak Hour 0.81 trips/student (61% in, 39% out) 259 166 425 School Afternoon Peak Hour 0.58 trips/student (42% in, 58% out) 128 177 305 Commute PM Peak Hour 0.17 trips/student (43% in, 57% out) 38 51 89 Source: Heffron Transportation, January 2019. a. Institute of Transportation Engineers, 2017. Private K-12 School (LU 536) rates applied to the proposed school capacity of 525 students. 2.4. Existing Trips to be Removed The proposed school would replace the previous use on the site, which was a QFC supermarket. Table 3 summarizes the average rates and trip estimates for each peak hour; these trips would be eliminated with the removal of the supermarket use. Table 3. Estimate of Existing Vehicle Trips to be Removed Vehicle Trip Estimate Time Period Trip Rate a Inbound Outbound Total Daily 106.78 trips/1,000 sf (50% in, 50% out) 2,170 2,170 4,340 AM Peak Hour 3.82 trips/1,000 sf (60% in, 40% out) 93 62 155 School Afternoon Peak Hour 3 7.67 trips/1,000 sf (51% in, 49% out) 159 153 312 Commute PM Peak Hour 9.24 trips/1,000 sf (51% in, 49% out) 192 184 376 Source: Heffron Transportation, January 2019. a. Institute of Transportation Engineers, 2017. Supermarket (LU 850) rates applied to the existing building size of 40,664 sf. b. ITE does not provide afternoon trip rates for Supermarkets. Based on hourly parking counts conducted at four Eastside QFC supermar- kets, as documented in “Kirkland Parkplace: QFC Parking Demand Survey Results” (Heffron Transportation, Inc., July 7, 2015) a factor of 0.83 was applied to the PM peak hour trip rate to estimate the trip rate during the school afternoon peak hour. Renton Excel Charter School School Traffic and Parking – Phase 1 Scoping January 25, 2019 | 6 2.5. Net New Trips Net new vehicle trips consist of the total trips generated by the school minus the trips that would be elimi- nated by removal of the grocery store. As shown in the previous tables, the school is expected to generate about 3,000 fewer trips per weekday than the supermarket, as supermarkets tend to generate traffic steadily during all hours that they are open, while the majority of school-generated traffic is concentrated in the morning and afternoon peak hours. The difference would be even more pronounced on weekends, when the school would generate very few trips and supermarkets typically generate their highest volumes of traffic. Table 4 summarizes the net new trips for each peak hour. As shown, the proposed school is expected have the highest traffic generation during the AM peak hour, when it is projected to generate 270 net new trips. During the afternoon and commute PM peak hours, the school is expected to generate fewer trips than what would be generated by the supermarket. Table 4. Net New Vehicle Trips Generated by the Proposed Project Morning Peak Afternoon Peak PM Peak In Out Total In Out Total In Out Total Proposed School 259 166 425 128 177 305 38 51 89 Existing Supermarket -93 -62 -155 -159 -153 -312 -192 -184 -376 Net New Trips 166 104 270 -31 24 -7 -154 -134 -287 Source: Heffron Transportation, Inc., January 2019. 3. Trip Distribution and Assignment Trip distribution for the proposed school was based on zip code data for the students attending the exist- ing Excel Charter School. The majority of students (82%) reside in Renton and Kent. The remaining 18% come from areas in all directions that include Covington, Auburn, Federal Way, and Seattle. Distribution of supermarket-generated trips was estimated based upon residential land use patterns in the vicinity, lo- cation of other supermarkets in the vicinity, and area traffic patterns.2 Figure 3 shows the estimated trip distribution patterns for both the existing and proposed uses at the site. The project-generated trips and existing trips to be removed were assigned to the street network based upon their respective distributions. Figure 4 shows the net new trips (project-generated trips minus the existing trips) projected to result from the project. Table 5 summarizes the net new trips projected through five intersections in the vicinity of the site. As shown, the highest numbers of net new trips are expected to occur during the AM peak hour at the nearest intersections located to the south of the site. As shown in Table 4, trips generated by the site are expected to decrease overall during the afternoon and commute PM peak hours. During the afternoon peak hour, while a net decrease is projected overall, the figure shows that intersections nearest the site to the south are projected to experience an increase. During the commuter PM peak hour, the project is expected to result in a decrease in trips through all intersections. Requirements for analysis of off-site intersections will need to be confirmed with the City. 2 Traffic patterns estimated from the City of Renton’s traffic flow map (2012). 01.25.2019 RENTON EXCEL Charter School Project Site SE 192nd St116thAve SESE 168th St SE 196th St SE Petrovitsky RdBenson Dr S SE 208th St 140thAve SE148thAve SESW 7th St 167 405SWGradyWy SE 200th St 124thAve SE108thAve SEN Not to Scale 19% 32% 2% 2% 10% 4% 5% 8% 2% 4% 4% 5% 2% 1% 9% 3% 0% 11% 0% 0% 8% 9% 9% 11% 12% 9%0% 9%9%5% Figure 3 Trip Distribution Existing and Proposed Uses Legend Inbound trip route Outbound trip route #% #% Distribution percentage - Renton Excel School (proposed use) Distribution percentage - Supermarket (existing use) 01.25.2019 RENTON EXCEL Charter School Project Site SE 192nd St116thAve SESE 168th St SE 196th St SE Petrovitsky RdBenson Dr S SE 208th St 140thAve SE148thAve SESW 7th St 167 405SWGradyWy SE 200th St 124thAve SE108thAve SEN Not to Scale [-17] (-2) 28 10 (5) [-1] 30 (-9) [-32] [-30] (1) 20 [0] (6) 7 [-15] (5) 16 [-2] (31) 82 63 (-21) [-70] 12 (-4) [-14] [-12] (0) 8 [-65] (-1) 39 [0] (50) 51 [2] (20) 46 36 (11) [-4] 22 (22) [-3] 29 (28) [3] [-34] (-16) 15 10 (-7) [-28] -2 (-8) [-14] -2 (-10) [-15] -3 (-11) [-16] [-14] (-10) -3 2 (-9) [-16] 2 (-6) [-14] 8 (-2) [-14][-18] (-7) 13 16 (5) [-15] 36 (11) [-4] [-3] (22) 22 30 (-9) [-32] [-1] (5) 10 29 (28) [3] [2] (20) 46 [-15] (-12) -4 -3 (-10) [-14] -1 (-6) [-10] [-10] (-7) -1 79 (33) [3] 18 (-1) [-13] 13 (6) [2] -1 (-14) [-21] [-20] (-11) 0 [-65] (-1) 39 63 (-21) [-70] 12 (-4) [-14] -3 (-11) [-16] [2] (6) 13 [1] (5) 11 7 (7) [2] [-14] (-10) -3 -2 (-8) [-14] [-12] (3) 12 [6] (49) 49 [2] (9) 8 [-30] (1) 20 [-12] (0) 8 [-34] (-16) 15 10 (-7) [-28] [-16] (-9) 2 2 (-6) [-14] 8 (9) [3] [-18] (-7) 13 8 (-1) [-14] [-17] (-2) 28 [-20] (-13) -4 -5 (-15) [-20] 7 (6) [0] 51 (50) [0] [-2] (31) 82 [-15] (-10) -2 Figure 4 Net New Trips [-19] (-17) -7 -11 (-18) [-21] Legend X (X) [X] Inbound trip route Outbound trip route Net new trip - AM peak hour Net new trip - Afternoon peak hour Net new trip - Commute PM peak hour Renton Excel Charter School School Traffic and Parking – Phase 1 Scoping January 25, 2019 | 9 Table 5. Net New Vehicle Trips Through Vicinity Intersections Intersection AM Peak Hour Afternoon Peak Hour Commute PM Peak Hour SE 168th Street / 108th Avenue SE 25 -18 -62 SE 168th Street / 116th Avenue SE 15 -62 -121 SE Petrovitsky Road / 108th Avenue SE 133 81 -2 SE Petrovitsky Road / 116th Avenue SE 255 54 -163 SE 192nd Street / 116th Avenue SE 111 6 -95 Source: Heffron Transportation, Inc., January 2019. 4. On-Site Circulation As shown on Figure 2, the proposed site configuration would provide an L-shaped family-vehicle loading zone along the northeast side of the school building. School bus loading would occur in a designated area to the east of the family-vehicle loading area. Both loading areas could be access directly from the school building without crossing any vehicle traffic lanes. Vehicles would circulate through the loading areas in a counterclockwise direction. The proposed parking area would have spaces angled to facilitate one-way traffic through each aisle. The proposed layout for parking and loading would minimize the number of potential vehicle conflict points within the site. Family vehicles would be directed to approach the student loading area from the northwest; the desig- nated loading area would have capacity for about 11 vehicles. Heffron Transportation has conducted nu- merous traffic analyses for schools throughout the region, and has consistently observed that morning drop-off activity is typically spread out over a longer period, with vehicles stopping only long enough for students to unload. With these typical characteristics, it is expected that the proposed loading zone length would be adequate to accommodate morning drop-off, without queues extending past the loading area. The maximum queue is expected to occur in the afternoon, when family vehicles line up to wait for dismissal. During this period, it is likely that the number of waiting vehicles would exceed the length of the loading zone. The school would develop and implement a queue management plan, utilizing available space in the parking lot drive aisles, to ensure that queues do not block access or parking for other busi- nesses in the Cascade Village development. In addition to direction on vehicle queuing locations, plan elements could also include encouragement to stagger arrivals so that a portion of vehicles arrive after dismissal, reminder of “good neighbor” rules not to block parking or access for nearby businesses, stationing of staff on site to direct loading during the periods of peak activity and help enforce rules, and written communication of these directives provided in hard copy to families and on the school’s website. 5. Parking Assessment 5.1. Existing Parking Demand The peak period driveway counts described previously were compiled to estimate peak parking demand at the existing school. The data indicated a peak parking demand of 22 vehicles, which equates to an overall rate of 0.13 parked vehicles per student during the school day. 5.2. Project-Generated Parking Demand Application of the derived parking demand rate described above to the proposed enrollment capacity of 525 students results in an estimated peak parking demand of 68 vehicles; this would be accommodated with 71 spaces proposed on site (60 long-term spaces plus 11 short-term/visitor spaces in the loading zone areas). Renton Excel Charter School School Traffic and Parking – Phase 1 Scoping January 25, 2019 | 10 However, without management measures, the addition of driving-age high school students to the school population could add to the parking demand. It is expected that without management measures, the pro- posed school would generate parking demand somewhere between public and private school rates. Limited available ITE data combined with data collected by Heffron Transportation for other school projects re- flects a parking rate between 0.30 and 0.40 vehicles per student for private schools with driving-age stu- dents that have parking supply available to accommodate them. ITE indicates a peak parking rate of 0.23 vehicles per student for High Schools (LU 530), thought it should be noted that as a combined middle and high school, the proposed school would have a lower percentage of driving-age students. In order to reduce potential for school-generated parking impacts during the day, it is recommended that the school develop and implement a Transportation Management Plan (TMP), to increase use of alterna- tive modes (bus, walking, biking, and carpool) by faculty, staff, and students, and reduce parking demand. The TMP could include measures such as transit incentives, carpool incentives, carpool match support, increased school bus service, and/or parking enforcement, as well as a family communication plan that provides direction for the identified measures. It should be noted that implementation of a TMP would also likely reduce school-generated trips below the levels projected in this memorandum. Parking demand for some evening school events could potentially exceed the on-site supply. This could be mitigated by encouraging carpooling, limiting the size of events (e.g. holding middle school and high school events on separate nights), and/or developing agreements with other nearby businesses that do not generate evening parking demand to lease or share their parking during events. 6. Summary of Findings The proposed Excel Charter School would renovate an existing building (previously a supermarket) lo- cated at in the Cascade Village commercial development in Renton. The school would serve grades 6 through 12 with an enrollment capacity of 525 students. The school is expected have the highest traffic generation during the AM peak hour, when it is projected to generate 270 net new trips. During the after- noon and commute PM peak hours, the school is expected to generate fewer trips than what would be gen- erated by the supermarket. During the afternoon peak hour, while a net decrease is projected overall, inter- sections nearest the site are projected to experience an increase. During the commuter PM peak hour, the project is expected to result in a decrease in trips through all intersections. Requirements for analysis of off-site intersections will need to be confirmed with the City. The proposed layout for parking and loading would minimize the number of potential vehicle conflict points within the site. Family vehicles would be directed to approach the student loading area from the northwest. It is expected that the proposed loading zone length would generally be adequate to accommo- date morning drop-off. The maximum queue is expected to occur in the afternoon, when parents line up to wait for dismissal. It is recommended that an on-site queueing plan be developed and implemented by the school to ensure that queues do not block access or parking for other businesses in the Cascade Village de- velopment. Without parking management measures, it is expected that school-generated parking demand would ex- ceed the proposed on-site supply of 60 spaces. In order to reduce potential school-generated parking im- pacts during the day, it is recommended that the school develop and implement a Transportation Manage- ment Plan (TMP), to increase use of alternative modes (bus, walking, biking, and carpool) by faculty, staff, and students. Parking demand for some evening school events could also potentially exceed the on-site supply. This could be mitigated by encouraging carpooling, limiting the size of events (e.g. holding middle school and high school events on separate nights), and/or developing agreements with other nearby busi- nesses that do not generate evening parking demand to lease or share their parking during events.