CCP 02-26-2001 - Laserfiche WebLink

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. f I~ ~tl . 3.0 Traffic Operations Analysis Methodology A traffic operations analysis is a process that estimates the quality and capacity of traffic flow along segments of roadway and through intersections. The traffic operations analysis included; detennining level of service and queue lengths for each of the key intersections. From these analyses, deficiencies in the roadway system were defined. The next step was to develop, evaluate and present roadway improvements or mitigation strategies for these deficiencies. The following sections detail the methodology and standards followed in this Traffic Study. 3.1 Level of Service Summary The approach to the traffic operations analysis is derived from the established methodologies documented in the Highway Capacity Manual, Third Edition, 1997. The Highway Capacity Manual (HCM) contains series of analysis techniques that are used to evaluate the operation of transportation facilities under specified conditions. Sycnchro5 and SimTraffic5, Highway Capacity Manual implementing operation analysis software packages, were used to analyze the key intersections. . The results of an HCM analysis are typically presented in the form of a letter grade (A-F) that provides a qualitative indication of the operational efficiency or effectiveness. The letter grade assigned to HCM analysis results is referred to as Level of Service (LOS). By definition, LOS A conditions represent high-quality operations (i.e., motorists . experience very little delay or interference) and LOS F conditions represent very poor operations (i.e., extreme delay or severe congestion). In accordance the Minnesota Department of Transportation guidelines, this study uses the LOS D / E boundary as the indicator of acceptable traffic operations. 3.2 Queue Summary Using only a capacity analysis to determine impacts would neglect potential queuing issues resulting from the background traffic or proposed development. A queue is defined as a line of one or more vehicles waiting to be serviced by the system. For this analysis, the system is represented by a signalized or unsignaIized intersection. A queuing analysis was also conducted to determine if adequate storage length for left and right turn lanes exists and will be available for future conditions. In addition, the queuing analysis indicates issues with through-traffic spilling back into the upstream intersection. . The storage length for this Traffic Study is defined as the length of the turn lane (not including the length ofthe taper into the turn lane) or the distance between intersections (from the near side of the downstream intersection to the far side of the upstream intersection). The queue lengths reported for the analysis were the 95th percentile queues that are expected to occur during the peak hour. In some instances, the 95th percentile queue length may exceed the storage length only once during the peak hour; however, the queue length is still reported as exceeding the storage length. Walgreen's Traffic Impact Study Draft Report Traffic Operations Methodology February 07, 2001 3-1