Project Information

Overview

The State Route 4 Bypass project (Bypass) is a roadway project being developed by a cooperative effort between Contra Costa County and the Cities of Antioch, Brentwood and Oakley.  The purpose of the Bypass is to ease traffic congestion in Brentwood and Oakley and to provide access to the growing areas of southeast Antioch and western Brentwood.  The Bypass will replace existing State Route 4 from just south of the Main Street Interchange to the existing intersection with Marsh Creek Road.  It is expected that Caltrans will relinquish the existing highway and accept the Bypass as the new State Route 4 sometime between 2008 and 2010.  The primary source of funds for the program is from fees collected on all new development in eastern Contra Costa County.

 

FREQUENTLY ASKED QUESTIONS (FAQ)

What is Being Proposed?  The State Route 4 Bypass (Bypass) Phase 1 project is a large, regional transportation project being constructed in three segments.  Segment 1 extends from just east of the SR4/Hillcrest Avenue Interchange to Lone Tree Way in the City of Antioch and will consist of a 6-lane freeway between existing SR4 and the Laurel Road Interchange and a 4-lane freeway from there to Lone Tree Way .  Phase 1 of Segment 2 has been constructed as a 2-lane Expressway from Lone Tree Way to Balfour Road with plans to convert it to a full freeway with interchanges at Sand Creek Road and Balfour Road .  Segment 3 extends from Balfour Road south to Marsh Creek Road as a 2-lane Expressway, then along Marsh Creek Road (East-West Connector) as a 2-lane conventional highway, connecting to existing SR4 (Byron Highway).  In addition, Vasco Road has been extended from Walnut Boulevard to Marsh Creek Road to directly connect to the Bypass at Marsh Creek Road .

Right of way is also being acquired and/or preserved for the ultimate transportation corridor from SR4 on the north end to Vasco Road on the south end to accommodate an 8-lane divided freeway with transit in the median as well as land necessary for the future interchanges at Sand Creek Road, Balfour Road, Marsh Creek Road and Walnut/Vasco Road.

What are the Project Limits?  The Bypass project starts approximately half way between the Hillcrest Avenue/SR4 Interchange in the City of Antioch and the Main Street/SR4 Interchange in the City of Oakley and continues south to Marsh Creek Road (approximately 8.5 miles) in the City of Brentwood in eastern Contra Costa County . The Bypass continues on Marsh Creek Road (upgraded roadway) to its intersection with existing SR4 ( Byron Highway ), approximately 12.4 miles in total length. 

Why do we need the Project?   The Bypass will accomplish the following:

1)    Provide access to the growing areas of southeast Antioch and western Brentwood ;

2)     Ease traffic congestion in Antioch , Brentwood , and Oakley; and

3)    Provide improved local circulation/mobility for Antioch , Oakley and Brentwood residents.

The Bypass project, when complete, will become the new State Route 4 through the Cities of Antioch and Brentwood and Contra Costa County .  It is anticipated that Caltrans will adopt the Bypass as the new State Route 4 and relinquish the existing highway in the 2009/2010 time frame

What is the history of the project?  The Bypass was born out of the East County Corridor Study of the late 1980s prepared by Caltrans, Contra Costa and Alameda Counties , the City of Antioch , Brentwood and Livermore and the Contra Costa Water District. The study identified feasible alternatives for a transportation corridor between State Route 4 in eastern Contra Costa to Interstate 580 in Alameda County .  A preferred alternative was adopted in the study and the northern part of this alternative became the initial alignment of the Delta Expressway, later known as the State Route 4 Bypass.  The Bypass is being developed and constructed by a cooperative effort between Caltrans, Contra Costa County and the cities of Antioch , Brentwood and Oakley. 

Who is building the project?  In 1989, the State Route 4 Bypass Authority was created through a Joint Powers Agency Agreement to deliver the SR4 Bypass Project.  This agency, which includes Contra Costa County and the Cities of Antioch , Brentwood and Oakley, has been working with Caltrans since the 1989 to implement the project.

How will the project be paid for?  The principal source of revenue for the Bypass program is from a regional transportation-funding agency, the East Contra Costa Regional Fee and Financing Authority (ECCRFFA).  This fee is currently collected on new development in eastern Contra Costa County .

Have any portions of the project been completed yet? Phase 1 of the State Route 4 Bypass, as described above is now fully constructed.

What is the Cost of the Project?  The total estimated cost of Phase 1 of the SR4 Bypass Project is approximately $216 million.  The first phase of Segment 1 is estimated to cost approximately $106 million when complete, the first phase of Segment 2 was around $29 million and the first phase of Segment 3 is estimated to cost $81 million. These costs include environmental, engineering, right of way acquisition, utility relocations and construction and construction management. 

Project Map - Segment 1

Project Map - Segment 2

Project Map - Segment 3 (Balfour Road to Marsh Creek Road)

Project Map - Segment 3 (Marsh Creek Road to Vasco Road at Walnut Blvd)

Project Map - Segment 3 (Marsh Creek Road)

Aerial Map - Segment 1, 2 & 3

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