Draft Environmental Impact Report - East Bay Municipal Utility District

Estates Reservoir Replacement Draft Environmental Impact ReportTraffic and CirculationTABLE 3.6-1Signalized Intersection Level of Service CriteriaLevelof ServiceDescriptionOperations with very low delay occurring with favorableAprogression and/or short cycle lengths.Operations with low delay occurring with good progression and/orBshort cycle lengths.Operations with average delays resulting from fair progressionC and/or longer cycle lengths. Individual cycle failures begin toappear.Operations with longer delays due to a combination of unfavorableprogression, long cycle lengths, and/or high volume-to-capacityDratios. Many vehicles stop and individual cycle failures arenoticeable.Operations with long delays indicating poor progression, long cycleE lengths, and high volume-to-capacity ratios. Individual cyclefailures are frequent occurrences.Operations with delays unacceptable to most drivers occurring dueFto over saturation, poor progression, or very long cycle lengths.Source: Highway Capacity Manual (Transportation Research Board, 2000).Average ControlDelay per Vehicle(Seconds)< 10.0> 10.0 to 20.0> 20.0 to 35.0> 35.0 to 55.0> 55.0 to 80.0> 80.0Unsignalized IntersectionsTraffic conditions at unsignalized intersections were evaluated using the method fromChapter 17 of the 2000 Highway Capacity Manual. With this method, operations are definedby the average control delay per vehicle (measured in seconds) for each movement that mustyield the right-of-way. For all-way stop-controlled intersections, the average control delay iscalculated for the intersection as a whole. This incorporates delay associated withdeceleration, acceleration, stopping and moving up in the queue. At two-way or side streetcontrolledintersections, the control delay (and LOS) is calculated for each controlledmovement, the left-turn movement from the major street, and the entire intersection. Forcontrolled approaches composed of a single lane, the control delay is computed as the averageof all movements in that lane. The delays for the entire intersection and for the movement orapproach with the highest delay are reported. Table 3.6-2 summarizes the relationshipbetween delay and LOS for unsignalized intersections.TABLE 3.6-2Unsignalized Intersection Level of Service CriteriaLevel of ServiceDescriptionAverage Control Delayper Vehicle (Seconds)A Little or no delays < 10.0B Short traffic delays > 10.0 to 15.0C Average traffic delays > 15.0 to 25.0D Long traffic delays > 25.0 to 35.0E Very long traffic delays > 35.0 to 50.0F Extreme traffic delays with intersection capacity exceeded >50.0Source: Highway Capacity Manual (Transportation Research Board, 2000).sb09_001.doc 3-6.2 7/22/2009