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<br />III. LEVEL OF SERVICE DEFINED <br />Future traffic operations are analyzed in this Study in terms of levels of service. Level of <br />service (LOS) is an estimate of the quality and performance of transportation facility <br />operations. Methodology outlined in the 2000 Highway Capacity Manual (HCM) is <br />commonly used to determine LOS. (This analysis used Synchro signal timing software to <br />model the study intersections with HCM LOS methodology). The degree of traffic <br />congestion and delay is rated using the letter “A” for the least amount of congestion to the <br />letter “F” for the highest congestion level (i.e., LOS A through LOS F). <br />The following categories provide general descriptions of the different levels of service <br />defined in the HCM: <br />• LOS A represents a free-flow condition. Travel speeds are at or near the speed limit <br />and little to no delay exists. Freedom to select desired speeds and to make turns and <br />maneuver within the traffic stream is very high. Average delays experienced at <br />unsignalized or signalized intersections are less than 10 seconds per vehicle. <br />• LOS B represents a zone of stable flow. Drivers still have reasonable freedom to <br />select their travel speeds. Minor average delays of 10 to 15 seconds per vehicle are <br />experienced at unsignalized intersections, and from 10 to 20 seconds per vehicle for <br />signalized intersections. <br />• LOS C still falls within the zone of stable flow, but travel speeds and vehicle <br />maneuverability are more closely controlled by the higher volumes. The selection of <br />speed is not affected by the presence of other vehicles, and maneuvering within the <br />traffic stream requires vigilance by the driver. Average delays of 15 to 25 seconds per <br />vehicle are experienced at unsignalized intersections and from 20 to 35 seconds for <br />signalized intersections. <br />• LOS D approaches unstable flow. Travel speed and freedom to maneuver are <br />somewhat restricted, with average delays of 25 to 35 seconds per vehicle at <br />unsignalized intersections and from 35 to 55 seconds for signalized intersections. <br />Small increases in traffic flow can cause operational difficulties at this level. <br />Northwestern College Master Plan 2 13529.000 <br />Traffic and Parking Impact Study