Route 238 is defined as follows in section 538, subdivision (a), of the
California Streets and Highways Code: Route 238 is from
Route 680 in
Fremont to
Route 61 near
San Lorenzo via
Hayward. Route 238 was never fully constructed to extend to near San Lorenzo as it is defined, as was
SR 61's proposed southern extension from that highway's current southern terminus in
San Leandro. Also, former portions of Route 238 have been relinquished by the state to the city of
Hayward. However, section 538 subdivision (b) further mandates that the city must still "maintain within their respective jurisdictions signs directing motorists to the continuation of Route 238". In addition, subdivision (c) permits the state to relinquish the remaining conventional highway portion of Route 238 located in Hayward to the city. Route 238 is part of the
California Freeway and Expressway System and is part of the
National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the
Federal Highway Administration (FHWA).
SR 238 SR 238 runs from
I-680 in
Fremont to
Union City,
Hayward and
I-580 in
Castro 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 to
San Jose at its intersection with
US Route 101 (US 101). Locally, it is designated
Mission Boulevard from I-680 to the intersection with
SR 92 and
SR 185 (which continues as Mission Boulevard) in Hayward. It is designated as
Foothill Boulevard in northern Hayward from A Street to I-580. In
Downtown 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. This
loop of one-way streets is known as the "Hayward Loop".
Mission Boulevard Mission Boulevard, the former
El Camino Viejo and
El Camino Real, is the road that passes in front of
Mission San José, the historic
Spanish 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 through
San Leandro and
Oakland. Since it runs along the base of the hills, Mission Boulevard nearly coincides with the
Hayward 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 to
Mission Santa Clara de Asís. Mission Boulevard joins the historic centers of the
Mission San Jose and
Niles districts of Fremont (formerly independent towns), the Decoto district of
Union City (formerly an independent town), and
Hayward.
I-238 Although the I-238 goes in an east–west direction from
Castro Valley to
San Leandro, the
California 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 with
I-580 and SR 238 in Castro Valley. From there, it enters into the southern portion of the
census-designated place of
Ashland, running parallel to its border with
Cherryland. Then, after entering San Leandro, I-238 ends at its northern (geographically western) terminus with
I-880. I-238 and I-880 are used as an alternate truck route between Castro Valley and
Oakland; trucks over are prohibited through the latter on I-580.
I-238 numbering I-238 does not follow established
rules for numbering Interstates as there is no I-38. As it connects two auxiliary routes of
I-80, it would normally use a three-digit number ending in 80, but, of the nine possible numbers, two (
180 and
480) 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 an auxiliary route of I-80 instead. ==History==