CA 4:


Segment Type of Highway
I-80 to Cummings Skyway 4-lane Expressway
Cummings Skyway to CA 160 at Antioch Freeway
Antioch to I-5 at Stockton 2-lane road
Follow I-5 north for a short distance.
I-5 to CA 99 Freeway
Follow CA 99 south for a short distance.
CA 99 to 3/4-mile west of the Stanislaus / Calaveras County Line 2-lane road
3/4-mile west of the Stanislaus / Calaveras County Line to Copperopolis 2-lane Expressway
Copperopolis to east of Angels Camp 2-lane road; Expressway proposed: ROW was purchased for the Angels Camp Bypass in 2001 and 2002.
East of Angels Camp to CA 89 2-lane road

Future Improvements:
A 4-lane expressway routing is being built for CA 4 between Antioch and Byron. The highway is being built in stages, with some parts initially being built as a super-2 expressway. The eastern end of the expressway will connect to Vasco Road, which will probably be widened to 4 lanes south to Livermore by 2020.

The State Route 4 Bypass Authority describes the project in these words:   “The State Route 4 Bypass project 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 2006 and 2008.  The primary source of funds for the program is from fees collected on all new development in eastern Contra Costa County.”

The authority, which is composed of one representative each from the City Councils of Antioch, Brentwood and Oakle and the County Board of Supervisors, also has a map of the project available.

CalTrans stated in June 2005 that it expects the bypass to be opened by autumn 2007.

Related Links and Pictures:

  • CA 4 at California Highways

  • CA 4 at West Coast Roads



Written by Eric Smith using California Highways and TerraServer. Also thanks to Steve Boland and the State Route 4 Bypass Authority.

Last Updated: 8/30/05

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