SU0004916 - Laserfiche WebLink

Home Browse Search

UNSIGNALIZED INTERSECTIONS At unsignalized intersections,at least one signal warrant(based on Caltrans Traffic Signal Warrant analysis)must be met before a traffic signal can be considered as a potential mitigation.The LOS is reported for the minor approach as well as for the whole intersection.Depending on the availability of gaps,the minor approach might L be operating at LOS D, E,or F while the intersection as a whole operates at LOS C or better. A minor approach that operates at LOS D,E,or F does not automatically translate into a need for a traffic signal.There are many instances in which only a few vehicles are experiencing LOS D,E,or F on the minor approach(such as heavy ,r right-tum traffic)while the whole intersection operates at an acceptable LOS.A signal is usually not warranted under such conditions. Of the 47 study intersections, 19 are existing intersections and of these, 15 are unsignalized.The method of unsignahzed intersection capacity analysis used in this section is from Chapter 10,"Unsignalized Intersections," of the Highway Capacity Manual, Special report No. 209(Transportation Research Board 2000).This method applies to intersections controlled by two-way STOP signs or YIELD signs(or three-way intersections controlled by a one-way STOP sign or YIELD sign).For intersections controlled by four-way STOP signs,LOS is based on the average control delay experienced on all approaches.At such intersections,drivers on the minor street are forced to use judgment when selecting gaps in the major flow through which to execute crossings or turning maneuvers.Thus,the capacity of the controlled legs of an intersection is based on three factors: 1) the distribution of gaps in the traffic stream on the major street, �. 2) driver judgment in selecting gaps through which to execute desired maneuvers,and 3) followup time required to move into the front-of-queue position. The LOS criterion'for intersections controlled by two-way STOP signs(Table 4.11-5)is different from the criterion used for signalized intersections because drivers expect a signalized intersection to carry higher traffic volumes than unsignalized intersections.Additionally,several driver behavior conditions combine to make delays _ at signalized intersections less onerous than at unsignalized intersections. The LOS criterion for roadway links in the county is LOS C,except on gateway roadways within the MHMP area where the acceptable LOS was changed to LOS D by MHMP EIR Mitigation Measure 4.12-5 (e).MHMP gateway road segments include Grant Line Road from the county line to Mountain House Parkway,Mountain House Parkway from Byron Road to I-205, and Byron Road from the county line to Wicklund Road. Table 4.11-5 Level-of-Service Criteria for Unsignalized Intersections _ Level of Service Delay Control Delay/Vehicle(sec/vehicle) A Little or no delay 0-10 B Short traffic delays >10-15 C Average traffic delays > 15-25 D Long traffic delays >25-35 E Very long traffic delays >35-50 F Extreme traffic delay >50 Source: Transportation Research Board 2000 College Park at Mountain House Specific Plan III Draft EIR EDAW San Joaquin County 4.11-17 Transportation