.svg)  Interstate 238 and State Route 238 | ||||
|---|---|---|---|---|
 I-238 highlighted in red; SR 238 in purple | ||||
| Route information | ||||
| Maintained byCaltrans | ||||
| Length | 16.519 mi[1][2] (26.585 km) | |||
| History | Designated 1934 (as SR 9) July 1, 1964 renumbered SR 238[3] Northernmost portion designated I-238 in May 1983 byFHWA[4] | |||
| Component highways |
| |||
| Major junctions | ||||
| South end |  I-680 inFremont | |||
| Major intersections | ||||
| North end |  I-880 inSan Leandro | |||
| Location | ||||
| Country | United States | |||
| State | California | |||
| Counties | Alameda | |||
| Highway system | ||||
| ||||
Route 238, consisting ofState Route 238 (SR 238) andInterstate 238 (I-238), is a mostly north–southstate andauxiliary Interstate highway in theSan Francisco Bay Area ofCalifornia. The southern segment is signed as SR 238 and is a divided multilane surface highway that runs parallel to the Hayward hills betweenI-680 inFremont andI-580 inCastro Valley. The northern segment is signed as I-238 and is a six-lane freeway that runs more east–west between I-580 andI-880 inSan Leandro.
The numbering of I-238 does not fit within theusual 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 ofI-80 (the primary two-digit Interstate in the Bay Area) were already being used in the state.
Route 238 is part of theCalifornia Freeway and Expressway System[5] and is part of theNational Highway System,[6] a network of highways that are considered essential to the country's economy, defense, and mobility by theFederal Highway Administration (FHWA).[7]
SR 238 runs fromI-680 inFremont toUnion City,Hayward andI-580 inCastro Valley parallel to the Hayward hills. Until I-680 was completed in the area and supplanted it completely as a through route, SR 238 extended south toSan Jose at its intersection withUS Route 101 (US 101). Locally, it is designatedMission Boulevard from I-680 to the intersection withSR 92 andSR 185 (which continues as Mission Boulevard) in Hayward. It is designated asFoothill Boulevard in northern Hayward from A Street to I-580.
InDowntown Hayward immediately north of SR 92, northbound traffic continues along the original SR 238 alignment on Foothill Boulevard, while southbound traffic is diverted onto A Street and Mission Boulevard. Thisloop of one-way streets is known as the "Hayward Loop".[8]
Mission Boulevard, the formerEl Camino Viejo andEl Camino Real, is the road that passes in front ofMission San José, the historicSpanish Mission founded in 1797, for which the road is named. Mission Boulevard proceeds in both directions from the Mission, but mainly northwest (the former El Camino Viejo) through Fremont, Union City, and Hayward. At the north end of Hayward, it changes its name to East 14th Street, which continues as a major thoroughfare going throughSan Leandro andOakland. Since it runs along the base of the hills, Mission Boulevard nearly coincides with theHayward Fault, a major earthquake fault, for almost the entire length of the Boulevard. The southern direction from the Mission San José is the former El Camino Real route toMission Santa Clara de Asís.
Mission Boulevard joins the historic centers of theMission San Jose andNiles districts of Fremont (formerly independent towns), the Decoto district ofUnion City (formerly an independent town), andHayward.
Although the 2.23-mile-long (3.59 km) I-238 goes in an east–west direction fromCastro Valley toSan Leandro, theCalifornia Department of Transportation (Caltrans) officially signs it as a north–south freeway since the rest of SR 238 is more north–south. The southern (geographically eastern) terminus of I-238 is at its interchange withI-580 and SR 238 in Castro Valley. From there, it enters into the southern portion of thecensus-designated place ofAshland, running parallel to its border withCherryland. Then, after entering San Leandro, I-238 ends at its northern (geographically western) terminus withI-880.
I-238 and I-880 are used as an alternate truck route between Castro Valley andOakland; trucks over 4.5 short tons (4.1 t; 4.0 long tons) are prohibited through the latter on I-580.[9]
I-238 does not follow establishedrules for numbering Interstates as there is no I-38. As it connects two auxiliary routes ofI-80, it would normally use a three-digit number ending in 80, but, of the nine possible numbers, two (180 and480) were in use by State Routes (the latter an Interstate until 1968 though SR 480 was deleted in 1991), and the remainder were already in use by other California auxiliary routes. (I-880 was designated at the same time as I-238.) I-238 is treated as auxiliary route of I-80 instead.
 State Route 9 | |
|---|---|
| Location | Fremont–Santa Cruz |
| Existed | 1934–1963 north ofSR 17 |
Before California massivelyrenumbered its state highways in 1964, SR 238 was part ofSR 9, which extended south toSan Jose andSanta Cruz.[3]
For several decades, SR 238 fromI-680 in Fremont to Hayward was planned to be upgraded to a freeway, called the "Mission" or "Foothill" freeway.[3] The segment was submitted to the Interstate Highway System in October 1968 but was rejected.[4] Then, after years of various lawsuits and appeals,Caltrans decided to cancel the project in 2003 and sell off the property it had acquired in the name ofeminent domain along the proposed route.[3][10]
As an alternative, SR 238 was proposed to be expanded from two lanes in each direction to three lanes in each direction along the majority of its width. Various other improvements began in July 2010,[11] followed by theCalifornia State Legislature relinquishing control of SR 238 within Hayward to local control in 2012.[3] In March 2013, the routing in Downtown Hayward was changed to include a one way circulation known as the "Hayward Loop", designed to improve traffic flow between SR 238, SR 185, and SR 92.[8]
The section of road that is now I-238 had no signed number before the1964 renumbering; it waspre-1964 Legislative Route 228 (along with an unbuilt extension west to unbuiltSR 61, which is still included in the SR 238 definition). The segment was then built as a freeway in 1956.[2]
When I-880 was added to the Interstate Highway System as a renumbering of part ofSR 17, the short piece of SR 238 connecting I-880 to I-580 was also added; both were non-chargeable routes (not eligible for Interstate Completion funds). Both numbers—I-238 and I-880—were approved by theAmerican Association of State Highway and Transportation Officials (AASHTO) on July 7, 1983.[4] The interchanges with I-580 and I-880 were rebuilt from 1988 to 1994, in part to add missing ramps between I-238 and I-880 toward the south.[2] Prior to the completion of the ramps, access was provided by Hesperian Boulevard.
On July 7, 1983, while approving the designation, AASHTO said:
This is to inform you that your application for the elimination ofRoute 180 and extension of Route 580, and the establishment of Route 880 and Route 238 have been approved.
However, since the I-238 designation does not fit the overall national numbering sequence and was necessitated only because allthree[-digit] combinations of I-80 have been used, the Committee has a further option to offer for your consideration. If the I-580 designation [were] continued from Castro Valley to San Lorenzo and then used in place of the proposed I-880 designation northerly to Oakland and over existing I-180 between Albany and San Rafael, then existing I-580 between Castro Valley and Oakland could be designated I-180. The Committee does recognize this option would involve considerable resigning, however.
On July 27, 1983, Caltrans responded:
We already have aState Route 180 in our Fresno area, and this route is separated from I-580 in Castro Valley by about 100 miles [160 km]. We are therefore unable to recommend the designation of existing I-580 between Castro Valley and Oakland as I-180.[12]
With the decommissioning of SR 480 in 1991, the "480" designation was once again made available. However, there has been no push since then to renumber I-238 to I-480.
In September 2006, a project began to reconstruct the entire length of I-238, including a reconfigured interchange with I-880 and an added travel lane in each direction. Additionally, almost all the bridges and overpasses were replaced with new ones meeting currentearthquake resistance standards. The project was completed in October 2009, six months ahead of schedule.[13]
The entire route is inAlameda County.
| Location | mi [1][2][14] | km | Exit[15] | Destinations | Notes |
|---|---|---|---|---|---|
| Fremont | 0.00 | 0.00 | Mission Boulevard | Continuation beyond I-680; formerSR 21 south | |
| I-680 –San Jose,Sacramento | Interchange; southern end of SR 238; I-680 exit 16 | ||||
| 3.31 | 5.33 |   SR 84 west (Mowry Avenue) –Centerville District,Newark,Dumbarton Bridge | South end of SR 84 overlap | ||
| 3.64 | 5.86 |  SR 84 east (Niles Canyon Road) / Niles Boulevard –Sunol,Livermore,Niles District | North end of SR 84 overlap | ||
| Union City | 6.78 | 10.91 | Decoto Road –Decoto District,Dumbarton Bridge | ||
| Hayward | 9.32 | 15.00 |  Alquire Parkway, Industrial Parkway toI-880 | Northern end of state maintenance | |
| 9.94 | 16.00 | Tennyson Road | |||
| 11.20 | 18.02 |   Harder Road toSR 92 /I-880 –San Mateo Bridge | |||
| 12.61 | 20.29 | SR 92 (Jackson Street) toI-880 –San Mateo Bridge,San Mateo,San Jose | No northbound access; south end of "Hayward Loop"one-way pair where northbound traffic continues on Foothill Boulevard and southbound traffic joins from Mission Boulevard | ||
  SR 185 north (Mission Boulevard north) / A Street west | Northbound access is via a left turn on A Street; southbound traffic turns left from A Street west onto Mission Boulevard south | ||||
| 13.12 | 21.11 | A Street | North end of "Hayward Loop"one-way pair where southbound traffic is diverted onto A Street west | ||
| Hayward–Castro Valley line | Southern end of state maintenance | ||||
| Castro Valley | 13.98 | 22.50 |   I-580 west (MacArthur Freeway) –Oakland | Interchange; northbound exit and southbound entrance; I-580 exit 34 | |
 I-580 east (MacArthur Freeway) –Stockton | Interchange; northbound exit only | ||||
| 14.29 | 23.00 | Castro Valley Boulevard, Mattox Road | Interchange northbound and at-grade intersection southbound | ||
| Northern end of SR 238; southern end of I-238 Freeway | |||||
| 14.47 | 23.29 | 14 | I-580 (MacArthur Freeway) –Oakland,Stockton | Southbound left exit and northbound left entrance; I-580 exit 34 | |
| Ashland | 14.93 | 24.03 | 15 | SR 185 (East 14th Street, Mission Boulevard) | Mission Boulevard not signed northbound despite the name change when SR 185 cross I-238 |
| San Leandro | 16.03 | 25.80 | 16A |  I-880 south (Nimitz Freeway) –San Jose,San Mateo Bridge | Northbound exit and southbound entrance; formerSR 17 south; I-880 north exit 31A |
| 16.28 | 26.20 | 16B | Hesperian Boulevard –San Lorenzo | Northbound exit and southbound entrance | |
| 16.68 | 26.84 | 17A | Washington Avenue | Northbound exit and southbound entrance | |
| 16.70 | 26.88 | 17B |  I-880 north (Nimitz Freeway) –Oakland | Northbound exit and southbound entrance; northern end of I-238; formerSR 17 north; I-880 south exit 31 | |
1.000 mi = 1.609 km; 1.000 km = 0.621 mi
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| Lists | |
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Routes initalics are no longer a part of the system. Major Interstates are highlighted. | |
