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Level of Service (signalized) <br />Signal progression is extremely favorable. Most vehicles arrive during the <br />A green phase and do not stop at all. Short cycle lengths may also contribute to '10.0 or less <br />the very low vehicle delay. <br />Operations characterized by goad signal progression andlor short cycle <br />B lengths_ More vehicles stop than wOh LOS A. causing higher lev+eks of average 10.1 to 20.0 <br />vehicle deiaV. <br />Higher delays may result from fair signal progression andJor longer cycle <br />lengths_ Individual cycle failures may begin to appear at this level_ The number 20.1 to 35.0 <br />of vehicles stopping is significant, though some vehicles may still pass through <br />the intersection without stopping. <br />The influence of congestion becornes more noticeable_ Longer delays may <br />G result from some combination of unfavoraW signal progression, long cycle _1 to 55.0 <br />lengths, or high volurne-to-capacity (VIC) ratios_ Many vehicles stop and <br />indMdual cycle failures are €noticeable_ <br />This is considered to be the limit of acceptable delay. These high de lay values <br />E generalh/ indicate poor signal progression, long cycle lengths, and high volume- 55.1 to 80.0 <br />to -capacity {VII) ratios. IndMdual cycle failures accurfreq uenth:,_ <br />Tris Wvel of delay is considered unacceptable by most drivwers_ This condition <br />often occurs with oversabiratioa7, that is, -rh5en arrival flow rates exceed the greater than 80.0 <br />capacity of the intersection. Poor progression and long cycle lengths mai+ also <br />be maGor contribAng causes of such delay levels_ <br />Sc..:rce: Transportation Research Board_ 20,f'rghvmy Capacjty Manuaf ('Nashington, D.C., 20M) p10-16. <br />