02/10/2003 Council Packet - Laserfiche WebLink

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• Level of Service Defined Future traffic operations are analyzed in this report in terms of levels of service. Level of service (LOS) is an estimate of the quality and performance of transportation facility operations. Highway Capacity Softward (HCS) using methodology outlined in the 2000 Highway Capacity Manual (HCM) is commonly used to determine LOS. The degree of traffic congestion and delay is rated using the letter "A" for the least amount of congestion to the letter "F" for the highest congestion level (i.e., LOS A through LOS F). The following categories provide general descriptions of the different levels of service defined in the HCM: • LOS A represents a free -flow condition. Travel speeds are at or near the speed limit and little to no delay exists. Freedom to select desired speeds and to make turns and maneuver within the traffic stream is very high. Average delays experienced at unsignalized or signalized intersections are less than 10 seconds per vehicle. • LOS B represents a zone of stable flow. Drivers still have reasonable freedom to select their travel speeds. Minor average delays of 10 to 15 seconds per vehicle are experienced at unsignalized intersections, and from 10 to 20 seconds per vehicle for signalized intersections. • LOS C still falls within the zone of stable flow, but travel speeds and vehicle maneuverability are more closely controlled by the higher volumes. The selection of speed is not affected by the presence of other vehicles, and maneuvering within the traffic stream requires vigilance by the driver. Average delays of 15 to 25 seconds per vehicle are experienced at unsignalized intersections and from 20 to 35 seconds for signalized intersections. • LOS D approaches unstable flow. Travel speed and freedom to maneuver are somewhat restricted, with average delays of 25 to 35 seconds per vehicle at unsignalized intersections and from 35 to 55 seconds for signalized intersections. Small increases in traffic flow can cause operational difficulties at this level. • LOS E represents operating conditions at or near the capacity of the intersection. Average delays of 35 to 50 seconds per vehicle are experienced at unsignalized intersections and from 55 to 80 seconds at signalized intersections. Freedom to maneuver within the traffic stream is very difficult. Any incident can be expected to produce a breakdown in traffic flow with extensive queuing.