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Home My Public Portal About2021-12-02 - Deinhard Lane Operational Analysis - 10-18-21 690 S. Industry Way, Suite 10 | Meridian, ID 83642 | www.NV5.com | Office 208.342.5400 | Fax 208.342.5353 MEMORANDUM To: Craig Groves/Park Pointe Development Date: October 18, 2021 From: John Karnowski, PE, PTOE, AICP / NV5 Project: Deinhard Lane Extension McCall, ID CC: Bonnie Layton/NV5 Subject: Traffic Operations and Safety Review EXECUTIVE SUMMARY This study reviews the Deinhard Lane Extension proposed east of S. Samson Trail and the planned development east of the Payette Lakes Middle School and Barbara Morgan Elementary School. The intent is to examine the potential changes that would benefit the schools while providing access to new development. The intersection of Deinhard Lane and S. Samson Trail, the “Four Corners” is envisioned to provide mixed-commercial uses on the northwest corner that complement the existing schools and community. The community is in a region of proposed infrastructure growth including new roadways, the SH -55 at Deinhard By-pass, and expansion of multi-use and transit infrastructure. The project site is anticipated to have about 525 new homes. There are multiple existing spurs that will allow neighborhood to access the greater road network although the main spine road through the neighborhood will direct most motorists to Deinhard Lane. This study reviewed the projected trips that Project Area Overview will use Deinhard Lane. The intersections of Deinhard Lane at SH -55 and S. Samson Trail and the traffic operations along the extension of Deinhard Lane were reviewed in detail to identify any potential deficiencies or safety concerns to the school operations. The traffic analysis included a review of the project site and both future residential developments west of S Samson Trail. The review indicates that the roadway network will operate acceptably with the proposed development. Westbound delay at Deinhard Lane at SH-55 is anticipated. This intersection is shown in the McCall Transportation plan to be the eastern terminus of the SH 55 Bypass that continues northwest to W Lake Street. Based on our review of the geometry, growth, and planned improvements shown in the McCall Area Transportation Plan, 2017 the foll owing are recommended: School Circulation Plan – The current road functions essentially as a series of individual driveways instead of a parkway and is not conducive to thru traffic. Crestline Engineering prepared a concept layout for Deinhard Lane from Samson Trail to the entrance to the new residential development. Given that configuration, the following are recommendations to improve school traffic and provide for connection to the neighborhood: • Modify the school driveways to create radial connections with Deinhard Lane with turn lanes, as appropriate. • Add additional width on the south side of the road to allow for pull-off area to avoid blocking traffic along Deinhard Lane during special events (see discussion below). This is to accommodate school traffic. 11 ft outside lane Increase shoulder to 8 ft • Review school drop-off and pick-up circulation to ensure optimal on-site queueing for peak periods. • Review pedestrian connectivity between neighborhoods and adjacent roadways to accommodate the pedestrian volumes and provide adequate crossing locations. • Identify and reduce conflict points for pedestrian, carpool, and bus traffic mobility. • Pedestrian flashers and cross walks should be illuminated during school hours to ensure safety as well as the preparation of an on-site circulation plan for parents and staff. Intersection Re-alignment – The offset intersection of Deinhard Lane and S. Samson Trail should be modified to provide safe and efficient movement for vehicles and the increased pedestrian traffic between the Four Corners (school, neighborhood, and commercial). The existing spur road that allows for westbound traffic to access Samson Trail should be closed. The driveway to the first parking lot east of Samson Trail should be inbound only. Coordination with the Town is recommended including the proposed alignment of the SH -55 Bypass, starting at Deinhard Lane west of SH -55 as shown the McCall Area Transportation Plan. With enhancements to Deinhard Lane and modifications to the Samson Lane intersection, the residential development proposed for east of the schools will not be a detriment to the operations or safety of the schools or to other traffic in the area. Deinhard Lane at S Samson Trail –Facing East TECHNICAL ANALYSIS The Deinhard Lane Extension is a proposed plan to improve access on Deinhard Lane at the Payette Lakes Middle School & Barbara Morgan Elementary School. The plan will create a two-way roadway east of Samson Trail, with designated turn lanes, that will extend past the schools and connect to future roadways in this area. A project vicinity map is provided in Figure 1. This memo documents the review process and operational results associated with this proposed improvement. Fig 1 – Deinhard Lane Extension Concept Layout Existing Traffic Data Intersection turn movement counts were collected on June 17, 2021. These counts were recorded between 7:00 AM – 9:00 AM and 4:00 PM - 6:00 PM in order to isolate the AM and PM peak hour conditions. The data locations are as follow: Data collected intersections:  Deinhard Road and SH-55  Deinhard Lane and Samson Trail School Trip Generation, Trip Distribution, and Assignment As counts where not recorded while school was in session these counts do not reflect average conditions. To approximate conditions during the school year, school trips were estimated using standard ITE Trip Generation Rates and added to the existing traffic counts. Total trips for both Payette Lakes Middle School and Barbara Morgan Elementary School were calculated as indicated below. Table 1 – Trip Generation Land Use Category ITE Code Units Period Trip Rate Total Trips Enter Exit Elementary 520 450 Weekday (vpd) 1.89 775 50% 387 50% 388 AM Peak(vph) .67 301 54% 162 46% 139 PM Peak (vph) .17 76 48% 36 52% 40 Middle School 522 315 Weekday (vpd) 2.13 858 50% 429 50% 429 AM Peak(vph) .58 183 54% 99 46% 84 PM Peak (vph) .17 54 49% 26 51% 27 These trips were distributed assuming likely travel patterns to/from these schools. Figure 2 illustrates resultant AM and PM peak hour school trips. These trips were then added to the existing traffic volumes to estimate traffic conditions while school is in session. Figure 3 illustrates these total AM and PM peak hour conditions. Fig 2 – Peak Hour School Trips Fig 3 – Existing Peak Hour Plus School Trips Traffic Operations and Safety Review Intersection Level-of-Service (LOS) was evaluated using the Synchro 11 software developed in accordance with the Highway Capacity Manual HCM 6th edition. Typically, the minimum design LOS is LOS D for suburban roadways and intersections. For purposes of this review, the following intersections were evaluated: o Intersections  Deinhard Road and SH-55  Deinhard Lane and Samson Trail  Samson Trail and Driveway 1  Deinhard Lane and Driveway 2  Deinhard Lane and Driveway 3  Deinhard Lane and Driveway 4  Deinhard Lane and Driveway 5 Operational results for these locations are summarized in Table 2. Table 2 – Deinhard Lane Extension Traffic Conditions Intersection Control Approach AM Peak PM Peak LOS Delay LOS Delay Deinhard Road and SH-55 Signal Overall B 12.9 C 31.3 Eastbound A 9.1 C 23.9 Westbound A 10.3 F 80.5 Northbound B 13.0 B 14.1 Southbound B 16.4 B 14.7 Samson Trail and Deinhard Lane AWSC Overall B 10.8 A 8.7 Eastbound B 11.4 A 9.2 Westbound B 11.3 A 8.5 Northbound B 10.6 A 8.7 Southbound B 9.1 A 7.8 Samson Trail and Driveway 1 TWSC Overall 2.6 .9 Southbound A 9.0 A 9.0 Deinhard Lane and Driveway 2 TWSC Overall 2.1 1.9 Southbound A 9.2 A 8.6 Deinhard Lane and Driveway 3 TWSC Overall 1.2 1.2 Southbound A 9.0 A 8.5 Deinhard Lane and Driveway 4 TWSC Overall 4.9 4.7 Southbound A 8.9 A 8.5 Deinhard Lane and Driveway 5 TWSC Overall 7.8 7.6 Southbound A 8.5 A 8.4 Additional Operational and Safety Considerations During special events the 24’-26’ wide drive aisle is used by visitors as an area for overflow parking. Vehicles are parked on both sides of the drive aisle reducing the width of access for emergency vehicles and decreasing operational safety. Widening of Deinhard Lane on the school property as proposed would alleviate these concerns and improve emergency vehicle access to the schools during special events. Overflow Parking During Special Event Future Projects Traffic Data Four projects are proposed to be developed in the area, each brining their own traffic Three are future housing developments. Development Trip Generation, Trip Distribution, and Assignment To approximate conditions during the school year, Site trips were estimated using standard ITE Trip Generation Rates and added to the existing traffic counts to see the impact. Table 3– Trip Generation Land Use Category ITE Code Units Period (VPD) Trip Rate Total Trips Enter Exit Multi Family 221 420 Weekday 5.44 2,285 50% 1,142 50% 1,143 AM Peak .36 152 26% 39 74% 112 PM Peak .44 185 61% 113 39% 72 Residential 210 375 Weekday 9.44 3,540 50% 1,770 50% 1,770 AM Peak .74 278 25% 69 75% 209 PM Peak .99 371 63% 234 37% 137 Residential 210 240 Weekday 9.44 2,266 50% 1,133 50% 1,133 AM Peak .74 178 25% 44 75% 134 PM Peak .99 238 63% 150 37% 88 These trips were distributed assuming likely travel patterns. Figure 4 illustrates resultant AM and PM peak school hours. These trips were then added to the existing traffic volumes to estimate traffic conditions while school is in session. Figure 5 illustrates these total AM and PM peak hour conditions. Fig 4 – Sites Peak Hour Plus School Trips Fig 5 – Projected Sites Peak Hour Plus School Trips Projected AADT Roadway Segment Functional Class No. of Thru Lanes Left-Turn Treatment LOS D Thresholds (ADT) ADT Traffic Volumes Vol LOS Deinhard Lane, East of SH-55 Minor Arterial 1 No LT Lane 5,500 4,590 < D S Samson Trail, North of Deinhard Minor Arterial 1 No LT Lane 5,500 2,840 < D S Samson Trail, South of Deinhard Minor Arterial 1 No LT Lane 5,500 1,960 < D Projected AADT Plus Site traffic Roadway Segment Functional Class No. of Thru Lanes Left-Turn Treatment LOS D Thresholds (ADT) ADT Traffic Volumes Vol LOS Deinhard Lane, East of SH-55 Minor Arterial 1 No LT Lane 5,500 5,752 > D S Samson Trail, North of Deinhard Minor Arterial 1 No LT Lane 5,500 3,506 < D S Samson Trail, South of Deinhard Minor Arterial 1 No LT Lane 5,500 4,205 < D Fig 4 – Sites Peak Hour Plus School Trips Technical Traffic Conclusions As indicated in the above table, all locations will operate favorably under the proposed Deinhard Lane Extension. Westbound traffic at Deinhard Road and SH-55 experiences some undue delay however approach volume/capacity conditions are less than 0.90 and overall delay is acceptable. No further mitigation is recommended at this location.