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4.Minor Revisions to the Draft Environmental Impact Report Ir L. The existing lane configurations at each of the study intersections are shown in Figures 5 and 6 contained in Appendix C. Existing traffic volumes were determined by performing manual turning movement counts at each of the project intersections.' The manual turning movement counts were performed in during the wanner months with the intention of counting maximum .. production periods and in order to eliminate the need for seasonal adjustment factors.A seasenal Existing peak-hour turning movement volumes at the study intersections are presented in Figures 13 and 14 contained in Appendix C. Traffic volumes on freeways and freeway ramps were determined by reviewing data presented in previous environmental impact reports, data available on the Caltrans web site,and balancing with existing traffic counts on State Route 132. L In addition to manual turning movement counts, 24-hour machine counts were performed at various locations. The results of the counts are presented in Appendix C. The results of the counts verify the assumption that PM peak-hour analyses are not required for the project. Truck traffic originating from the existing mining sites in the project area was determined to be negligible during the PM peak hour of the adjacent roads relative to the AM peak-hour volumes. him Existing Levels of Service The concepts of capacity and level of service (LOS)are central to the analysis of all traffic facilities,although their meanings and the criteria are different for intersections and roadways, and differ between signalized and unsignalized intersections. At unsignalized intersections, "Stop"or"Yield"signs are used to assign the right-of-way to one street while controlling movements from the other street(s). This forces drivers on the controlled street to select gaps in the major street flow through which they can enter and tum into the intersection,or cross entirely through the intersection. r In analyzing the ability of traffic to use gaps in the major street flows,it is generally recognized that certain"critical"movements(i.e.,a traffic movement that requires crossing a conflicting traffic stream)are more able to use these gaps than others. A right tum from the minor street ►. represents the critical movement most able to use available gaps since the driver has to be concerned with gaps in only one direction of major street traffic. A left tum from the major street L is the next critical movement most able to use available gaps,followed by through movements and left turns from the minor street.Drivers making left turns from the minor street onto a major two-way street must recognize and negotiate their way through gaps in two directions of major street flows. This concept is important because it highlights the frequent capacity shortages for r vehicles seeking to make left turns from a minor street onto a major street. Key input data required to analyze unsignalized intersections include geometric characteristics 6. and peak-hour volumes. Geometric characteristics incorporated into the analysis include the number and use of lanes,lane markings,tum radii, approach angles,and sight distances. Six his t The counts were performed by the independent traffic-counting firm of Southland Car Counters(ander contract with Peters Engineering Group). .� Cemex Vernalis Quarry Mining and Reclamatbn Project 4-19 ESA/203015 Final Environmental Impact Report June 2W8