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Traffic Impact Study <br />Robinson Property <br /> <br /> <br /> <br />Alliant No. 221-0180.1 5 <br />June 30, 2022 <br />2.3 Traffic Operations Analysis <br />An existing conditions traffic operations analysis was completed using Synchro/SimTraffic <br />software to establish a baseline to which future traffic operations could be compared. Operations <br />analysis results identify a Level of Service (LOS) which indicates the quality of traffic flow <br />through an intersection. The LOS results are based on average delay per vehicle, which correspond <br />to the delay threshold values presented in Table 3. Intersections are given a ranking from LOS A <br />through LOS F. LOS A indicates the best traffic operation, with vehicles experiencing minimal <br />delays. LOS F indicates an intersection where demand exceeds capacity, or a breakdown of traffic <br />flow. The LOS D/E threshold for overall intersection operations is often used as the indicator of <br />congestion in an urban area. For through/stop intersections, a key measure of operational <br />effectiveness is the side-street LOS. Long delays and poor LOS can occur on side-street <br />approaches even if the overall intersection is functioning well, making side-street LOS a valuable <br />design criterion. <br />Table 3 – Level of Service Criteria <br /> <br />After LOS, the second component of the traffic operations analysis is a study of vehicular queuing, <br />or the lineup of vehicles waiting to pass through an intersection. An intersection can operate with <br />an acceptable LOS, but if queues from the intersection block entrances to turn lanes or adjacent <br />driveways, unsafe operating conditions could result. The 95th percentile queue, or the length of <br />queue with only a five percent probability of being exceeded during an analysis period, is <br />considered the standard for design purposes. <br />The existing traffic operations analysis was performed at the study intersections for the weekday <br />a.m. and p.m. peak hours. Results of the existing traffic operations analysis, presented in Table 4, <br />indicate that each study intersection currently operates at overall LOS A during the weekday a.m. <br />and p.m. peak hours. In addition, no significant side-street delay or queuing issues were observed <br />in the field or in traffic simulations. Detailed operations and queuing analysis results are presented <br />in Appendix A. <br /> <br />Description Signalized <br />Intersection <br />Unsignalized <br />Intersection <br />A Free Flow: Low volumes and no delays.0 - 10 0 - 10 <br />B Stable Flow: Speeds restricted by travel conditions, minor delays.> 10 - 20 > 10 - 15 <br />C Stable Flow: Speeds and maneuverability closely controlled due to higher volumes.> 20 - 35 > 15 - 25 <br />D Stable Flow: Speeds considerably affected by change in operating conditions. <br />High density traffic restricts maneuverability, volume near capacity.> 35 - 55 > 25 - 35 <br />E Unstable Flow: Low speeds, considerable delay, volume at or slightly over capacity.> 55 - 80 > 35 - 50 <br />F Forced Flow: Very low speeds, volume exceed capacity, long delays with stop and go <br />traffic.> 80 > 50 <br />Source: Highway Capacity Manual, 6th Edition, Transportation Research Board, Exhibits 19-8, 20-2, 21-8, 22-8. <br />Delay per Vehicle (seconds) <br />Level of Service