Interstate 238 and State Route 238 (California)
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.
Interstate 238 and State Route 238 | ||||
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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 |
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| Major junctions | ||||
| South end | I-680 in Fremont | |||
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| North end | I-880 in San Leandro | |||
| Location | ||||
| Country | United States | |||
| State | California | |||
| Counties | Alameda | |||
| Highway system | ||||
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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 because 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.