08-04-25 - City Council Work Session Agenda

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1.2. ANALYSIS METHODOLOGIES Synchro/SimTraffic 12" edition capacity analysis software was used to evaluate the operating conditions at stop -controlled and signalized intersections. Specialized roundabout analysis software Rodel was utilized for the capacity analysis of roundabouts. The capacity of an intersection quantifies its ability to accommodate traffic volumes and is expressed in terms of level of service (LOS), measured in average delay per vehicle. LOS grades range from A to F, with LOS A as the highest (best traffic flow and least delay), LOS E as saturated or at -capacity conditions, and LOS F as the lowest (oversaturated conditions). A 50-percent confidence interval was utilized for the Rodel analysis (the default value, representing the median results expected for an intersection). The LOS grades shown below, which are provided in the Transportation Research Board's Highway Capacity Manual (HCM), quantify and categorize the driver's discomfort, frustration, fuel consumption, and travel times experienced as a result of intersection control and the resulting traffic queuing. A detailed description of each LOS rating can be found in Table 1-1. Table 1-1: Level of Service Grading Descriptions Level of Description' A Minimal control delay; traffic operates at primarily free -flow conditions; unimpeded movement within traffic stream. B Minor control delay at signalized intersections; traffic operates at a fairly unimpeded level with slightly restricted movement within traffic stream. C Moderate control delay; movement within traffic stream more restricted than at LOS B; formation of queues contributes to lower average travel speeds. D Considerable control delay that may be substantially increased by small increases in flow; average travel speeds continue to decrease. E High control delay; average travel speed no more than 33 percent of free flow speed. F Extremely high control delay; extensive queuing and high volumes create exceedingly restricted traffic flow. Highway Capacity Manual, Th Edition. The range of control delay for each rating (as detailed in the HCM) is shown in Table 1-2. Table 1-2: Level of Service Grading Criteria Level of Service Average Control Unsignalized Intersections Delay (s/veh) at: Signalized Intersections 'Highway Capacity Manual, nth Edition 2All movements with a Volume to Capacity (v/c) ratio greater than 1 receive a rating of LOS F. At side -street stop -controlled intersections, overall delay is not reported, and the worst side street delay is reported in its place. The overall delay at side -street stop -controlled intersections can misrepresent the operating conditions at the intersection since most vehicles on the main road experience zero delay. Northwest Main — Lino Lakes, MN Traffic Impact Analysis I June 2025 Page 156 of 617