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Spack Consulting 2 of 2 Traffic Operations Study Addendum <br /> Line Avenue Corridor <br /> <br /> <br />Mitigation Options <br />The existing Line Avenue/Twin Lakes Road intersection provides the following geometry: <br /> One left turn lane, one thru lane, one right turn lane for the northbound approach <br /> One left turn/thru lane and one right turn lane for the southbound approach <br /> One lane for all movements for the eastbound and westbound approaches <br /> <br />To improve operations, the following mitigation options were considered: <br />1. Additional approach lanes with a change in traffic control, which can increase safety and capacity <br />by allowing more traffic through the intersection <br />2. All-way stop control, which can be implemented easily and provide more opportunity for side <br />street movements through the intersection <br />3. Single-lane roundabout control, which significantly improves safety, provides a calming effect by <br />slowing traffic, and can provide an increase in capacity <br /> <br />Results <br />An intersection capacity analysis was conducted for the existing intersections per the Highway Capacity <br />Manual, 2010. Intersections are assigned a “Level of Service” letter grade for the peak hour of traffic based <br />on the number of lanes at the intersection, traffic volumes, and traffic control. Level of Service A (LOS A) <br />represents light traffic flow (free flow conditions) while LOS F represents heavy traffic flow (over capacity <br />conditions). LOS D is considered acceptable at intersections. Individual movements are also assigned LOS <br />grades. At busy intersections, one or more individual movements may operate at a lower LOS when the <br />overall intersection is operating acceptably at LOS C or D. <br /> <br />The intersection was analyzed during the a.m. and p.m. peak hours for the following Scenarios: <br /> Existing conditions <br /> Existing geometry with Line Avenue disconnected between 3rd Street and 5th Street <br /> Two-Way stop control with additional approach lanes <br /> All-Way stop control with existing approach lanes <br /> Single-lane roundabout control <br /> <br />With the exception of the existing conditions, all scenarios were analyzed with the forecasted volumes <br />assuming Line Avenue is disconnected between 3rd Street and 5th Street. A summary of the LOS results for <br />these scenarios is shown in Table 1. The LOS calculations were completed with the VISTROTM software <br />package, which uses the methodology detailed in the Highway Capacity Manual 2010. The full LOS <br />calculations are attached to this memorandum. <br /> <br />Table 1 – Peak Hour Level of Service1 <br />Intersection A.M. Peak P.M. Peak <br />Existing Conditions and Volumes <br /> Line Avenue/Twin Lakes Road <br /> <br />A (c) <br /> <br />C (e) <br />Forecasted Volumes2 with <br /> Existing Geometry <br /> Two-Way and Added Approach Lanes <br /> All-Way Stop and Existing Geometry <br /> Single-Lane Roundabout Control <br /> <br />A (c) <br />A (c) <br />C (c) <br />A (b) <br /> <br />D (f) <br />C (f) <br />C (c) <br />B (b) <br />1The first letter is the Level of Service for the intersection. The second letter <br />(in parentheses) is the Level of Service for the worst operating movement. <br />