Interstate 238 and State Route 238 (California)

Interstate 238 and State Route 238
Interstate 238 and State Route 238
	I-238 highlighted in red; SR 238 in purple
Route information
	Maintained by Caltrans
Length	16.519 mi (26.585 km)
History	Designated 1934 (as SR 9); July 1, 1964 renumbered SR 238; Northernmost portion designated I-238 in May 1983 by FHWA
Component; highways	SR 238 from Fremont to Castro Valley; I-238 from Castro Valley to San Leandro;
Major junctions
South end	I-680 in Fremont
	SR 92 / SR 185 in Hayward; I-580 in Castro Valley;
North end	I-880 in San Leandro
Location
Country	United States
State	California
Counties	Alameda
Highway system
	Interstate Highway System; Main; Auxiliary; Suffixed; Business; Future; State highways in California; Interstate; US; State; Scenic; History; Pre‑1964; Unconstructed; Deleted; Freeways;

Route 238, consisting of State Route 238 (SR 238) and Interstate 238 (I-238), is a mostly north–south state and auxiliary Interstate highway in the San Francisco Bay Area of California. The southern segment is signed as SR 238 and is a divided multilane surface highway that runs parallel to the Hayward hills between I-680 in Fremont and I-580 in Castro Valley. The northern segment is signed as I-238 and is a six-lane freeway that runs more east–west between I-580 and I-880 in San Leandro.

The numbering of I-238 does not fit within the usual conventions of existing three-digit auxiliary Interstate Highways, where a single digit is prefixed to the two-digit number of its parent Interstate Highway as I-38 does not exist. The I-238 number was specifically requested by the state of California so it could match the California Streets and Highways Code and because all three-digit combinations of I-80 (the primary two-digit Interstate in the Bay Area) were already being used in the state.

^ Cite error: The named reference trucklist was invoked but never defined (see the help page).
^ California Department of Transportation (July 2007). "Log of Bridges on State Highways". Sacramento: California Department of Transportation.
^ Cite error: The named reference cah 238 was invoked but never defined (see the help page).
^ Faigin, Daniel P. (December 25, 2013). "Interstate Highway Types and the History of California's Interstates". California Highways. Self-published. Retrieved December 25, 2013.^{[unreliable source]}

[trucklist-1] Cite error: The named reference trucklist was invoked but never defined (see the help page).

[bridgelog-2] California Department of Transportation (July 2007). "Log of Bridges on State Highways". Sacramento: California Department of Transportation.

[cah_238-3] Cite error: The named reference cah 238 was invoked but never defined (see the help page).

[cah_Interstates-4] Faigin, Daniel P. (December 25, 2013). "Interstate Highway Types and the History of California's Interstates". California Highways. Self-published. Retrieved December 25, 2013.^{[unreliable source]}

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