11.15.23 BOA Agenda Packet - Laserfiche WebLink

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56 6.0 Intersection Capacity Analysis Capacity analyses (see Appendix) were performed for the AM and PM peak hours for the existing traffic condition and the projected future background and build-out traffic conditions using Synchro Version 11 software to determine the operating characteristics of the adjacent road network and the impacts of the proposed project. The NCDOT Congestion Management Group uses and reports Synchro Level-of-Service output for the analysis of intersection operating conditions. All capacity analyses are included in the Appendix and are briefly summarized in the following sub-sections. Capacity is defined as the maximum number of vehicles that can pass over a particular road segment or through a particular intersection within a set time duration. Capacity is combined with level-of-service (LOS) to describe the operating characteristics of a road segment or intersection. LOS is a qualitative measure that describes operational conditions and motorist perceptions within a traffic stream. The Highway Capacity Manual (HCM) defines six levels-of-service, LOS A through LOS F, with A representing the shortest average delays and F representing the longest average delays. LOS D is the typically accepted standard for signalized intersections in urbanized areas. For signalized and all-way stop controlled intersections, LOS is defined for the overall intersection operation. For two-way stop controlled unsignalized intersections, only the movements that must yield right-of-way experience control delay. Therefore, LOS criteria for the overall intersection is not reported by Synchro Version 11 or computable using methodology published in the Highway Capacity Manual. Table 6.0 lists the LOS control delay thresholds published in the Highway Capacity Manual for signalized and unsignalized intersections. Table 6.0 Level-of-Service Control Delay Thresholds Level-of- Signalized Intersections— Unsignalized Intersections—Average Service Control Delay Per Vehicle Control Delay [sec/veh] &Qualitative sec/veh Operational Description A s 10 <_ 10 B > 10—20 > 10— 15 Short Delays C > 20-35 > 15-25 D > 35—55 > 25—35 Moderate E > 55—80 > 35—50 Delays F > 80 > 50 Long Delays For all scenarios, existing PHFs were used at all intersections.