Page 478 - skylineranchdeir0709

4.F Traffic/Access

During the A.M. peak hour, the net volume of traffic traveling off-site and onto the
existing arterial roadway system is less than the total volumes noted above (residential trip ends
plus school trip ends) due to the fact that a number of project-generated trips are between the
project’s residential units and the on-site elementary school. For example, a vehicle traveling
from a home to the school and then back from the school to the home represents four of the
project’s calculated trip ends but does not add to the off-site trips. At the direction of County
staff, this analysis conservatively assigns 90 percent of the total A.M. residential trip ends as
off-site trips and assigns 10 percent of the elementary school’s trip ends as off-site trips. The
combined effect of these two factors is a net volume of trips leaving the project site during the
A.M. peak hour (654 vehicles) that is 8 percent less than the total amount of A.M. outbound trip
ends generated by the project’s residential units (711 vehicles). Independent of the proposed
project, the County will also require a traffic study to address the school site when a detailed site
plan for the school is developed by the District.

(2) Trip Distribution

The distribution of project trips is based on two scenarios; one using the existing roadway
system and the other based on the future roadway system to be in place under the Interim
SCVCTM. The proposed project would be accessed from a new roadway through the project
site (i.e., the proposed realignment of Whites Canyon Road). The realignment of Whites Canyon
Road, between Plum Canyon Road and Sierra Highway, was conditionally approved as Skyline
Ranch Road for the proposed project by the Los Angeles County Department of Public Works on
July 19, 2006. Further discussion of the realignment of Whites Canyon Road is provided in
Subsection (8)(a), Whites Canyon Road Extension.

Figure 4.F-4, Project Trip Distribution – Existing Roadways, on page 4.F-20 illustrates
the distribution of trips to be generated by the proposed project with existing roadways in place.
A total of 75 percent of the project trips would travel to and from a new intersection with Sierra
Highway. Of these, approximately 5 percent would travel to and from the northeast along Sierra
Highway, with the remaining 70 percent traveling to and from the southwest along Sierra
Highway and dispersing beyond that point, as shown in Figure 4.F-4. About 25 percent of the
project trips would travel to the more northerly intersection with the existing Plum Canyon Road,
with about 15 percent traveling to and from the north from that point (10 percent in the A.M. peak
hour due to school trips), and 10 percent traveling to and from the south (15 percent in the A.M.
peak hour due to school trips). Approximately 30 percent of project trips are anticipated to use
Highway 14 based on existing roads and commute patterns. About 25 percent of these trips
would use the Sierra Highway interchange to travel to and from the south, and approximately 5
percent would travel to and from the north utilizing the Sand Canyon Road interchange.

Figure 4.F-5, Project Trip Distribution – Future Roadways, on page 4.F-21 shows the
distribution of trips generated by the proposed project with construction of future roadways

County of Los Angeles Department of Regional Planning Skyline Ranch Project
PCR Services Corporation July 2009

Page 4.F-19
PRELIMINARY WORKING DRAFT – Work in Progress