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Mike Tassano December 6, 2022 <br />Page 6 of 39 <br />Table 1: Signalized Intersection LOS Criteria <br />Level of Service Description Delay in Seconds <br />A Progression is extremely favorable, and most vehicles arrive during the green phase. Most vehicles do not stop at all. Short cycle lengths may also contribute to low delay. < 10.0 <br />B Progression is good, cycle lengths are short, or both. More vehicles stop than with LOS A, causing higher levels of average delay. > 10.0 to 20.0 <br />C Higher congestion may result from fair progression, longer cycle lengths, or both. Individual cycle failures may begin to appear at this level, though many still pass <br />through the intersection without stopping. <br />> 20.0 to <br />35.0 <br />D <br />The influence of congestion becomes more noticeable. Longer delays may result from some combination of unfavorable progression, long cycle lengths, or high V/C ratios. Many vehicles stop, and the proportion of vehicles not stopping declines. Individual cycle failures are noticeable. <br />> 35.0 to 55.0 <br />E This level is considered by many agencies to be the limit of acceptable delay. These high delay values generally indicate poor progression, long cycle lengths, and high V/C ratios. Individual cycle failures are frequent occurrences. <br />> 55.0 to 80.0 <br />F <br />This level is considered unacceptable with oversaturation, which is when arrival flow rates exceed the capacity of the intersection. This level may also occur at high V/C ratios below 1.0 with many individual cycle failures. Poor progression and long cycle lengths may also be contributing factors to such delay levels. <br />> 80.0 <br />Source: Highway Capacity Manual 2000 Edition (Transportation Research Board). <br />Table 2: Unsignalized Intersection LOS Criteria <br />Level of Service Description Delay in Seconds <br />A Little or no delays ≤ 10.0 <br />B Short traffic delays > 10.0 to 15.0 <br />C Average traffic delays > 15.0 to 25.0 <br />D Long traffic delays > 25.0 to 35.0 <br />E Very long traffic delays > 35.0 to 50.0 <br />F Extreme traffic, delays where intersection capacity exceeded > 50.0 <br />Source: Highway Capacity Manual 2000 Edition (Transportation Research Board). <br />