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TABLE 1 <br /> LEVEL OF SERVICE(LOS)CRITERIA FOR INTERSECTIONS <br /> LEVEL OF CONTROL DELAY(SECONDS/VEHICLE) <br /> SERVICE TYPEOFFLOW DELAY MANEUVERABILITY SIGNALIZED UNSIGNALIZED ALL-WAY STOP <br /> A Stable Flow Very slight delay. Progression is very favorable, with Turning movements are easily < 10.0 <10 0 < 10.0 <br /> most vehicles arriving during the green phase not made,and nearly all dmcrs findofa - <br /> stopping at all. freedom of operation. <br /> B Stable Flow Good progression and/or short cycle lengths. More Vehicle platoons are formed. >10 and<20.0 m >10 and:S 15.0 >10 and< 15.0 <br /> vehicles stop than for LOS A, causing higher levels of Many drivers begin to feel <br /> average delay. somewhat restricted within <br /> groups of vehicles. <br /> C Stable Flow Higher delays resulting from fair progression and/or Back-ups may develop behind >20 and<35.0 >15 and<25.0 >15.and<25.0 �' <br /> longer cycle lengths. Individual cycle failures may turning vehicles. Most drivers <br /> begin to appear at this level. The number of vehicles feel somewhat restricted <br /> stopping is significant, although many still pass through <br /> the intersection without stopping. <br /> D Approaching The influence of congestion becomes more noticeable. Maneuverability is severely >35 and<55.0 >25 and�35.0 >25 and<35.0 <br /> Unstable Flow Longer delays may result from some combination of limited during short periods due <br /> unfavorable progression, long cycle lengths, or high to temporary back-ups. <br /> volume-to-capacity ratios. Many vehicles stop,and the <br /> proportion of vehicles not stopping declines. Individual <br /> cycle failures are noticeable. <br /> E Unstable Flow Generally considered to be the lunit of acceptable delay. There are typically long queues >55 and<80.0 >35 and<50.0 >35 and<50.0..'. <br /> Indicative of poor progression, long cycle lengths, and of vehicles waiting upstream of <br /> high volume-to-capacity ratios. Individual cycle the intersection. <br /> failures are frequent occurrences. <br /> F Forced Flow Generally considered to be unacceptable to most Jammed conditions. Back-ups >80.0 >50.0 >50.0 <br /> drivers. Often occurs with over saturation. May also from other locations restrict or <br /> occur at high volume-to-capacity ratios. There are prevent movement. Volumes <br /> many individual cycle failures. Poor progression and may vary widely, depending <br /> long cycle lengths may also be major contributing principally on the downstream <br /> factors. back-up conditions. <br /> References: 1.Highway Capacity Manual, Fourth Edition, Transportation Research Board, 2000. <br /> 2"d Draft DeSilva Gates Quarry Trak&Circulation Analysis 10 Ociober1005 <br /> Jones&Stokes (R90577S021/25-4000-02) <br /> L - I l I <br />