State Route 46 Corridor Improvement Project
The State Route 46 Corridor Improvement Project (Corridor Project) was initiated by the San Luis Obispo Council of Governments to improve operations on State Route 46 between Airport Road (post mile 32.2) in the City of Paso Robles to the east junction of State Routes 41 and 46 (post mile 57.8). The Corridor Project proposes to widen the existing two-lane highway to a four-lane divided expressway. The new roadway will be a four-lane, access-controlled, divided expressway. It will be constructed mostly on the existing alignment with a few sections of the new expressway on new alignments. Right-of-way will be purchased throughout the entire project. Much of the State Route 46 Corridor has been permitted and constructed at this time.
In April 2005, the California Department of Transportation (Caltrans) approved the Negative Declaration/Finding of No Significant Impact for the easternmost portion of the State Route 46 4-Lane Widening Project, which covered the conversion of 39.3 miles (Interstate 5 to Antelope Grade) in both San Luis Obispo and Kern counties to a four-lane divided expressway in both District 5 and District 6. Construction was completed between post miles 0.0 and 27.9 in Kern County. Construction of the remaining project near the town of Lost Hills (post miles 27.9 to 31.9) is expected to begin in April 2021; more information can be found on the District 6 Project Webpage.
The western portion of State Route 46 (US 101 to the Wye) was subsequently analyzed in a Final Environmental Impact Report/Finding of No Significant Impact for the State Route 46 Corridor Improvement Project, approved by Caltrans in May 2006. Construction of several sections including Union, Whitley 1, Whitley 2A, Whitley 2B, from post miles 32.2 to 50.2, has been completed.
Three additional sections remain to be constructed within District 5, the Cholame Section, the Wye Section, and the Antelope Grade Section, as discussed in more detail below.
- Cholame Section: This section extends from post mile 49.7 to 54.7. Modifications to the design of the previously identified preferred alternative of this section recently required a Final Supplemental Environmental Impact Report/Finding of No Significant Impact.
This was approved February 2020 and construction began in March 2022.
- Wye Section: This section of the Corridor Project extends from post miles 54.0 to 57.8. This section was analyzed in the 2006 Environmental Impact Report/Finding of No Significant Impact, and Alternative 8b was selected as the preferred alternative. The Wye Section is currently in the design phase and construction is anticipated in 2023.
- Antelope Grade Section: This section extends from San Luis Obispo post miles 57.3 to 60.9 and Kern County post miles 0.0 to 0.4. Design modifications to the preferred alternative previously analyzed in the 2005 Negative Declaration/Finding of No Significant Impact are currently in the design phase, and a supplemental environmental document will be prepared for changes proposed to this section. The draft environmental document is expected to be complete in early 2022.Construction is currently anticipated to commence in 2024, although the section is currently unfunded.
The Corridor Project purpose is to minimize fatal accidents, improve safety, and reduce existing and future peak-hour congestion on State Route 46 between Paso Robles and Cholame, a critical east-west corridor connecting the Central Coast and Central Valley areas of California. State Route 46 is one of the few east-west routes connecting Interstate 5 to U.S. Highway 101 and is a designated Focus Route in the State’s Interregional Transportation Strategic Plan. It primarily serves interregional and interstate traffic, although it is used daily by residents of the communities of Paso Robles, Cholame, Shandon, and Whitley Gardens. It is the major east-west route between State Route 166 to the south and State Route 156 to the north that can facilitate the movement of goods by truck.
The Corridor Project is needed due to current and predicted future traffic capacity problems as well as a higher than average collision rate within the Wye Section. The remaining two-lane sections of the corridor continue to experience peak-hour congestion. According to data collected in 2017, approximately 17% of the traffic volume were trucks and 60% of the trucks are 5-axle and larger. Limited passing opportunities cause traffic to back up behind slower moving vehicles along the remaining two-lane sections of the corridor and can increase the risk of collision as drivers attempt to pass and overtake slower vehicles.
- Federal Highway Administration
Estimated Funding Breakdown
Funding for the State Route 46 Corridor Improvement Project is comprised of local, state, and federal dollars. Local funding includes the support of the San Luis Obispo Council of Governments.
Sections of the Corridor Project that have already been constructed were Prop 1B funded through the Statewide Transportation Improvement Program with a combination of Corridor Mobility Improvement Account funds, the Statewide Transportation Improvement Program – Augmentation funds, Regional Transportation Improvement Program funds and Interregional Transportation Improvement Program funds.
Both the Cholame and Wye sections are fully funded for design, right-of-way and construction. Antelope Grade is currently unfunded.
|Section||Estimated Construction and Support|
|Antelope Grade (05-3307E)||$101,300,000|
Proposed Project Schedule
|Union||Completed - 2011|
|Whitley 1||Completed - 2014|
|Whitley 2A||Completed - 2016|
|Whitley 2B||Completed - 2018|
|Cholame*||Currently in Construction|
Currently in Design Phase,Anticipated Construction 2023
Currently in Design Phase,Anticipated Construction 2024
*Fully funded for design, right-of-way, and construction
Public Information Office, Caltrans District 5
Phone: (805) 549-3111
Jason Wilkinson, Senior Environmental Planner
Phone: (805) 540-9165
Project Manager, David Rasmussen
Phone: (805) 835-6328