Okaloosa County BOCC — 2013 meeting #1140 (date undetermined) — Nature Lake Traffic Analysis — reading text

22 872 588 1.53% WB Airport Rd/CR 188 SR 85 John Givens Rd EB D 1,460 6,774 0.94 0.95 0.0900 544 966 1,510 23% 37 1,547 (87) 2.52% WB Nature Lake Transportation Concurrency Analysis 7 Operational Analysis Operational analysis in the form of turn lane analyses was conducted for the project entrance on Lake Silver Road and the intersection of State Road 85 and Lake Silver Road. Lake Silver Road Project Entrance Location Criteria for determining right turn lane requirements are provided in "Intersection Channelization Guide," Transportation Research Board (NCHRP) Report Number 279. During the PM peak hour, it was conservatively estimated that nearly all of the project entering traffic would turn right into the project. Accordingly, it is estimated that 100 vehicles will turn right onto the project entrance road from Lake Silver Road. The westbound existing volume on Lake Silver Road (right plus through movements) is estimated to be 550 vehicles based on existing traffic and development plus committed traffic for projects located on Lake Silver Road. For the purposes of this analysis, a 35 mph design speed was used (the posted speed limit is 30 mph). As indicated in Figure 3, a right turn lane is not warranted at this location. Since no significant traffic volume is projected to turn left into the site from the west on Lake Silver Road, a left turn lane analysis is not applicable. State Road 85 Northbound Left Turn onto Lake Silver Road Criteria for examining left turn lane requirements are provided in "Aspects of Traffic Control Devices," Highway Research Record Number 211, National Research Council. While a left turn lane exists at this location, the purpose of this analysis was to determine the dimensional requirements of the northbound left turn lane based on total future northbound left turning traffic from State Road 85 onto Lake Silver Road. During the PM peak hour, it is estimated that 90 project vehicles will turn left onto Lake Silver Road from State Road 85. This results in a future estimated northbound total left turn volume of 250 vehicles during the PM peak hour. For the purposes of this analysis, a 60 mph design speed (55 mph posted) was used for State Road 85. As indicated in Figure 4, the deceleration plus conservative two-minute stacking storage length requirements for the left turn lane total 630 feet. The existing left turn lane is approximately 680 feet in length. Therefore, the existing left turn lane is adequate to accommodate the increase in traffic. Nature Lake Transportation Concurrency Analysis 8  Figure 3 Right Turn Lane Analysis Location: Westbound Right Turn into Project from Lake Silver Road Project: Nature Lake Guideline for determining the need for a major-road right-turn bay at a two-way stop-controlled intersection. INPUT Roadway geometry: 2-lane roadw ay 200 Right-Turn Volume, veh/h Variable Value 180 Add right - turn bay Major-road speed, mph: 35 160 Major-road volume (one direction), veh/h:* 550 140 Right-turn volume, veh/h: 100 120 100 80 OUTPUT Do not add right - turn bay 60 Variable Value 40 Limiting right-turn volume, veh/h: 145 20 Guidance for determining the need for a major-road right-turn bay for a 2-lane roadway: 0 200 300 400 500 600 700 800 900 1000 1100 1200 Do NOT add right-turn bay. Major-Road Volume (one direction), veh/h source: Evaluating Intersection Improvements: An Engineering Study Guide NCHRP Report 457 *note minimum volume of 250 for marker to indicate on chart. Posted speed is 30 mph Major road background volume estimated based on existing development + trips from committed projects as of December 2010 Nature Lake Transportation Concurrency Analysis 9  Figure 4 Turn Lane Dimensions Nature Lake Calculations Based on FDOT Guidelines Intersection NB Right from SR 85 onto Lake Silver Rd Scenario PM Peak Hour Date 7/26/2012 General Information: Turn Lane Type Left Approach NB Traffic Control Type Unsignalized Time of Day PM Number of Lanes 1 Geometric Conditions Rural Design Speed 60 mph Turn Lane Parameters: Vehicle Length 25 feet Peak Cycle Factor 30 Turning Traffic Volume 250 Storage: 2-Minute Stacking During Peak 15 Minutes 8.33 vehicles Total 2-Minute Stacking Needed 225 feet (rounded up to whole vehicles) Minimum Required Storage N/A Number of Turn Lanes 1 Design Storage Length per Lane 225 feet Deceleration: Taper 50 feet Total Deceleration Distance 405 feet Total Turn Length (including Taper) 630 feet Nature Lake Transportation Concurrency Analysis 10 Conclusion A traffic impact analysis was conducted for the proposed Nature Lake project, which will be located on the north side of Lake Silver Road approximately 0.68 miles west of State Road 85 in unincorporated Okaloosa County, Florida. The following is a summary of the findings and observations of this report:  The existing northbound left turn lane on State Road 85 turning left onto Lake Silver Road appears long enough to accommodate the proposed future traffic including this project.  The project access location on Lake Silver Road does not meet requirements for a left turn lane or a right turn lane. As a mitigation measure, however, the project proposes a right turn deceleration lane into the project to reduce delay for Lake Silver Road drivers traveling west, which is the afternoon peak direction.  Portions of State Road 85 and Airport Road are projected to be deficient prior to the addition of project traffic. The applicant proposes to address mitigation with a developers agreement with Okaloosa County. Nature Lake Transportation Concurrency Analysis 11  Exhibit 1 Supporting Data 21-Feb-2012 16:55:02 Page -218- of -367- 555RPT [1,0,0,2] 3_57_AXWOY.txt 2011 Weekly Axle Factor Category Report - Report Type: ALL County: 57 - OKALOOSA Week Dates 5713 5714 5716 5717 SR397 SR20,SR397 - WALT.CO OKALOOSA RURAL OKALOOSA URBAN 1 01/01/2011 - 01/01/2011 1.00 0.98 0.94 0.99 2 01/02/2011 - 01/08/2011 1.00 0.98 0.94 0.99 3 01/09/2011 - 01/15/2011 1.00 0.98 0.94 0.99 4 01/16/2011 - 01/22/2011 1.00 0.98 0.94 0.99 5 01/23/2011 - 01/29/2011 1.00 0.98 0.94 0.99 6 01/30/2011 - 02/05/2011 1.00 0.98 0.94 0.99 7 02/06/2011 - 02/12/2011 1.00 0.98 0.94 0.99 8 02/13/2011 - 02/19/2011 1.00 0.98 0.94 0.99 9 02/20/2011 - 02/26/2011 1.00 0.98 0.94 0.99 10 02/27/2011 - 03/05/2011 1.00 0.98 0.94 0.99 11 03/06/2011 - 03/12/2011 1.00 0.98 0.94 0.99 12 03/13/2011 - 03/19/2011 1.00 0.98 0.94 0.99 13 03/20/2011 - 03/26/2011 1.00 0.98 0.94 0.99 14 03/27/2011 - 04/02/2011 1.00 0.98 0.94 0.99 15 04/03/2011 - 04/09/2011 1.00 0.98 0.94 0.99 16 04/10/2011 - 04/16/2011 1.00 0.98 0.94 0.99 17 04/17/2011 - 04/23/2011 1.00 0.98 0.94 0.99 18 04/24/2011 - 04/30/2011