Chapter 1 - Caltrans - State of California

Chapter 3 Comments and Coordination
communities of Mussel Shoals, La Conchita, and Rincon Point, as well as the southern
area of the City of Carpinteria.
The Ventura/Santa Barbara 101 HOV Traffic study was used to determine the operational
benefits of the proposed improvements during peak traffic volume conditions on the
highway, while also considering the traffic conditions at the interchange intersections.
Furthermore, this study will analyze the impacts to motorists from Mussel Shoals and La
Conchita as a result of proposed median closures. To quantify such impact, it is more
appropriate to use peak hour turning movement data for these locations. As such, we
determined that mainline traffic volumes should be based on the peak hours of U.S. 101,
and interchange traffic volumes should be based on the peak hours of the interchanges.
This approach will result in a conservative data set and ensures that the peak traffic
conditions for the two study components are evaluated accurately.
Forecasted Traffic Volumes
The Department’s policy is to maintain freeway mainline and ramp operations at LOS
based on the Guide for the Preparation of Traffic Impact Studies (The Department’s,
December 2002).
The project study area is experiencing an average traffic growth rate of 1.05% to 1.30%
annually and long distance commuters are increasing, as affordable housing is located
further away from business and employment centers.
The Santa Barbara County Association of Governments (SBCAG) regional travel model
was used to develop annualized growth rates on the U.S. 101 mainline and ramps. Based
on total daily traffic forecasts for Year 2005 and Year 2030, a 1.8 percent annually
compounded growth rate was used to develop traffic forecasts for the Year 2015
(representing the project opening year) and Year 2035. This growth rate was applied to
Year 2008 traffic counts.
Intersections/Ramp Operation
Peak period intersection counts were conducted during the morning (7:00 to 9:00AM)
and evening (4:00 to 6:00PM) at the nine study intersections during a typical weekday
(Tuesday through Thursday) in April 2008. The data includes peak hour intersection
turning movements and cyclist and pedestrian volumes. The count data indicates that the
AM and PM peak hours vary among locations, further justifying the need to use sitespecific
peak hour volumes at the intersections.
During field reconnaissance, lane configurations, turning movement pocket lengths, and
speed limits were collected. The peak hour volumes presented in this report reflect minor
IS/EA VEN-SB US101 HOV Project 65