Chapter 1 - Caltrans - State of California

Chapter 3 Comments and Coordination
levels in the southbound direction. Between Seacliff exit and Bailard Avenue,
northbound U.S. 101 generally operates at LOS C during the AM peak. During the PM
peak, southbound U.S. 101 operates at LOS C between Bailard Avenue at Bates Road,
and LOS D between Bates Road and Seacliff.
The HCM methodology does not account for the impacts of downstream blockage or
capacity reductions. However, several projects are programed to improve the impacts of
the blockage. Several locations along the U.S. 101 corridor experience localized
congestion during the peak period. Field observations and travel time runs indicate that
northbound vehicle speeds between 7:00 and 8:00 AM slowed substantially near the lane
drop upstream from Mussel Shoals and between U.S. 101 interchanges with Bailard
Avenue and SR-150. At these locations, the U.S. 101 mainline section changes from
three lanes to two, and the merging activity creates congestion and slower speeds during
peak periods. Similar congestion points were not observed for SB PM traffic. SB U.S.
101 maintains a two-lane cross section through the study area and thus does not exhibit
the same merge conflict points as does NB U.S. 101.
MAINLINE LANE UTILIZATION OF HOV LANE
The proposed HOV lane would accommodate vehicles with two or more occupants.
Passenger occupancy counts were collected by the Department in September 2007. The
data indicates that approximately 25 percent of existing AM peak period traffic and
approximately 28 percent of existing PM peak period traffic had two or more passengers
per vehicle. Since these observed occupancy rates reflect existing local trends, it is
reasonable to assume future occupancy rates would be similar. Therefore, it was
assumed that the HOV lane would carry 25 percent of future AM peak traffic and 28
percent of future PM peak traffic.
NO BUILD Conditions Year 2015
Under 2015 NO BUILD conditions, the mainline would remain at its current
configuration. Therefore, the existing NB congestion during the AM peak hour would
continue to occur and likely worsen as volumes increase. NB U.S. 101 would operate at
LOS D from Seacliff to the Bates Road Interchange during the AM peak hour. SB traffic
operations would degrade to LOS D or worse from Bailard Avenue to Seacliff exit during
the PM peak hour and would continue to generate worse LOS conditions.
The following figure, Figure 2.1-7 shows 2015 Peak Hour Traffic Volumes for the NO
BUILD and BUILD Alternatives.
IS/EA VEN-SB US101 HOV Project 75