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Ryan Streff January 20, 2014 City of Arden Hills Page 3 The County Road E/Lexington Avenue intersection is currently signalized, while the County Road E/Arden Plaza East Access intersection is side-street stop controlled. The existing geometrics, traffic controls, and volumes within the study area are shown in Figure 2. Intersection Capacity Analysis An existing intersection capacity analysis was completed to establish a baseline condition to which future traffic operations could be compared. The existing study intersections were analyzed using a combination of Synchro/SimTraffic (Version 8.0) and the Highway Capacity Manual (HCM). Capacity analysis results identify a Level of Service (LOS) which indicates how well an intersection is operating. Intersections are ranked from LOS A through LOS F. The LOS results are based on average delay per vehicle, which correspond to the delay threshold values shown in Table 1. LOS A indicates the best traffic operation and LOS F indicates an intersection where demand exceeds capacity. Overall intersection LOS A through D is generally considered acceptable by drivers in the study area. Table 1.Level of Service Criteria for Signalized and Unsignalized Intersections Signalized Intersection Unsignalized Intersection LOS Designation Average Delay/Vehicle (seconds) Average Delay/Vehicle (seconds) A 10 10 B > 10 - 20 > 10 - 15 C > 20 - 35 > 15 - 25 D > 35 - 55 > 25 - 35 E > 55 - 80 > 35 - 50 F > 80 > 50 For side-street stop controlled intersections, special emphasis is given to providing an estimate for the level of service of the side-street approach. Traffic operations at an unsignalized intersection with side-street stop control can be described in two ways. First, consideration is given to the overall intersection level of service. This takes into account the total number of vehicles entering the intersection and the capability of the intersection to support these volumes. Second, it is important to consider the delay on the minor approach. Since the mainline does not have to stop, the majority of delay is attributed to the side-street approaches. It is typical of intersections with higher mainline traffic volumes to experience high levels of delay (i.e. poor levels of service) on the side-street approaches, but an acceptable overall intersection level of service during peak hour conditions. Results of the existing capacity analysis shown in Table 2 indicate that all study intersections currently operate at an acceptable overall LOS C or better during the midday and p.m. peak hours with the existing traffic control and geometric layout. The side-streets also operate acceptably with minimal delay. However, it should be noted that there is a minor queuing issue at the County Road E/Lexington Avenue intersection during the p.m. peak hour. Vehicles in the eastbound left-turn lane occasionally queue beyond the current turn lane storage, but do not impact the adjacent intersection.