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LJ 6. Estimate the average total delay for each of the subject movements and determine the level of service for each movement and for the intersection. Gaps are utilized by vehicles in the following priority order. 1. Right toms from the minor street 2. Left toms from the major street 3. Through movements from the minor street 4. Left toms from the minor street For example, if alert-fuming vehicle on the major street and a through vehicle from the minor street are waiting to cross the major traffic stream, the first available gap of acceptable size would be taken by the left-fuming vehicle. The minor street through vehicle must wait for the second available gap. In aggregate terms, a large number of such left-turning vehicles could use up so many of the available gaps that minor street through vehicles are severely impeded or unable to make safe crossing movements. Level of Service See the following table "Level of Service Criteria for Unsignalized Intersections" for the relationship between delay and level of service. LEVEL OF SERVICE CRITERIA FOR UNSIGNALIZED INTERSECTIONS AVERAGE DELAY LEVEL OF SERVICE DELAYS <_ 5 s/veh A Little or no delay > 5 and < 10 s/veh B Short traffic delays > 10 and <_ 20 s/veh C Average traffic delays > 20 and <_ 30 s/veh D Long traffic delays > 30 and S 45 s/veh ~ E Very long traffic delays Z 45 sfveh F Extreme traffic delays The level of service criteria for Two-way STOP controlled intersections is somewhat different from the criteria used in Chapter 9 for signalized intersections. The primary reason for this is the difference is that drivers expect a signalized intersection to cant' higher traffic volumes than unsignalized intersections. Additionally, several driver behavior considerations combine to make delays at signalized intersections less onerous than at unsignalized intersections. Reference: Highway Capacity Manual, Special Report 209, Transportation Research Boazd, Update October 1994 .._ ~e~' V APP