5.2. SR 08-08-2011 - Laserfiche WebLink

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right-out access at 173rd Avenue and 165th Avenue, and the full movement signalized intersection at 171St Avenue would be removed. Trip Assignment/Forecasted Traffic Volumes Turning movements at each intersection for each scenario were estimated by applying the approach direction distribution percentages to the site-generated traffic. In addition to the site-generated traffic, the background traffic growth was added to thru traffic on the development area roadways. This traffic was then added to the existing traffic to develop the future projected traffic volumes. Figures 21-5 thru 21-7 show the projected 2031 traffic volumes with an interchange at TH 10 / 169 and Twin Lakes Parkway for each scenario. Traffic Operations Analysis The traffic operations analysis is derived from established methodologies documented in the Highway Capacity Manua12000 (HCM). The HCM provides a series of analysis techniques that are used to evaluate traffic operations. Intersections are given a Level of Service (LOS) grade from "A" to "F" to describe the average amount of control delay per vehicle as defined in the HCM. The LOS is primarily a function of peak traffic hour turning movement volumes, intersection lane configuration, and the traffic controls at the intersection. LOS A is the best traffic operating condition, and drivers experience minimal delay at an intersection operating at that level. LOS E represents the condition where the intersection is at capacity, and some drivers may have to wait through more than one green phase to make it through an intersection controlled by traffic signals. LOS F represents a condition where there is more traffic than can be handled by the intersection, and many vehicle operators may have to wait through more than one green phase to make it through the intersection. At a stop sign-controlled intersection, LOS F would be characterized by exceptionally long vehicle queues on each approach at an all- way stop, or long queues and/or great difficulty in finding an acceptable gap for drivers on the minor legs at athrough-street intersection. The LOS ranges for both signalized and un-signalized intersections are shown in Table 21-2. The threshold LOS values for un-signalized intersections are slightly less than for signalized intersections. This variance was instituted because drivers' expectations at intersections differ with the type of traffic control. A given LOS can be altered by increasing (or decreasing) the number of lanes, changing traffic control arrangements, adjusting the timing at signalized intersections, or other lesser geometric improvements. LOS also changes as traffic volumes increase or decrease. City of Elk River Draft Alternative Urban Areawide Review July 2011 Page 60 of 84 ~i