Interstate 238 is a 2.23-mile freeway from I-880 in San Leandro to I-580 by northern reaches of Hayward in the San Francisco Bay area. The route functions as a connector between Interstate 580 east to the Central Valley and Interstate 880 to San Jose and Oakland. I-238 also serves as part of the truck route into Oakland, as trucks are prohibited on portions of I-580 in the city. Although orientated east to west, I-238 is signed north-south for continuity with adjacent California 238.

Interstate 238 is the only limited access portion of a much longer planned freeway corridor. The legislative route 238 is assigned to three branches:

  • SR 238 north along Mission and Foothill Boulevards from I-680 to I-580.
  • I-238 west from I-580 to I-800.
  • Unconstructed SR 239 north from I-880 to SR 61.

Historically, plans called for Mission Boulevard to be bypassed by a freeway on an alignment in the foothills; however, local opposition, lawsuits and funding concerns delayed action on this route. Plans advanced by 2005 to sell the right of way previously acquired for the new roadway, and to use the proceeds from the land sales to improve existing road facilities. Options for these funds included construction of a new grade separation at the intersection where California 92, 85 and 238 converge in Downtown Hayward and adding more lanes to the corridor. Construction underway in 2011 instead reconfigured the junction into a landscaped gateway into Downtown Hayward.

Widened in 2009, the middle segment comprises a five to six-lane freeway paralleling Lewelling Boulevard. The unbuilt section was envisioned to connect I-880 and I-580 with the often-proposed but never-constructed Southern Crossing. The Southern Crossing, which appeared on several mid-1960s General Drafting and Gousha maps, would have had approaches from I-238 and I-980; the freeways would have converged at a point near Oakland International Airport (OAK) on a new alignment of California 61 that likely would have been built on fill or causeway. The Southern Crossing would then cross San Francisco Bay, connecting with unconstructed California 230, I-380 and U.S. 101 near San Francisco International Airport (SFO).

238: An Unusual Number for an Interstate Highway

Unlike most other three-digit Interstate routes, I-238 has no parent route. The numbering anomaly arose due to the timing of its acceptance into the Interstate Highway System; at that time, all branch routes of Interstate 80 were reserved for other routes (I-180 was proposed for the Richmond-San Rafael Bridge and SR 480 was the designation for the former Embarcadero Freeway in San Francisco).

Interstate 238 was created in 1984 as a result of California State Assembly Bill 2741, which modified the route numbering for California 17 and Interstate 580 in the state highway system. This legislation introduced I-238 and I-980 in Oakland, as well as provided for an extension of I-580 to Marin County and creation of a new I-880 between San Jose and Oakland. Resigning of the routes affected by AB 2741 was completed in 1985.


Interstate 238 south
A flyover ramp passes overhead, taking motorists from I-238 northbound to I-880 south. Photo taken 07/04/06.
Ramps from the two-wye interchange joining I-880 (Nimitz Freeway) with Interstate 238 southbound converge above Hesperian Boulevard. The freeway leaves the San Leandro city limits and enters unincorporated Ashland here. Photo taken 03/27/17.
I-238 advances east with six overall lanes to a folded diamond interchange (Exit 15) with Mission Boulevard (SR 185). Photo taken 03/27/17.
SR 185 is a major arterial route that begins in Downtown Hayward and extends north along Mission Boulevard, 14th Street, and International Boulevard to SR 77 (42nd Avenue) in Oakland. Much of the route overlays former SR 17. Photo taken 03/27/17.
Exit 15 veers away from I-238 south to adjacent Lewelling Boulevard in a residential area of Ashland. Lewelling Boulevard intersects SR 185 (Mission Boulevard) nearby, which heads south through Cherryland to Hayward. Photo taken 03/27/17.
California 238 separates from I-238 at the ensuing off-ramp to Foothill Boulevard south. The continuation of the freeway mainline to I-580 is numbered as Exit 14. Photo taken 03/27/17.
The second and last confirming marker for Interstate 238 south stands above the Mission Boulevard (SR 185) underpass. Photo taken 03/27/17.
Foothill Boulevard extends south from I-580 initially along a wide right of way reserved for the unconstructed SR 238 freeway. The six-lane boulevard intersects Castro Valley Boulevard, the historic alignment of U.S. 50 through Castro Valley, on the south side of the freeway while en route to Downtown Hayward. Photo taken 03/27/17.
A green out covers an exit only placard for the loop ramp linking I-238 south with I-580 (MacArthur Freeway) northwest to Oakland and San Francisco. The mainline continues east with three lanes onto I-580 (Arthur Breed Freeway) east. Photo taken 03/27/17.
Exit 14 departs from the east end of Interstate 238 at the systems interchange with I-580 and Foothill Boulevard. I-580 continues from here to Dublin, Pleasanton, Livermore and Tracy (via I-205). Photo taken 03/27/17.
Interstate 238 north
Interstate 238 separates from I-580 west through the systems interchange with the MacArthur Freeway north to Oakland and Foothill Boulevard south into the city of Hayward. Photo taken 11/27/05.
I-238 advances west from Castro Valley to unincorporated Ashland as ramps from Foothill Boulevard (SR 238) and Castro Valley Road join the freeway from below. Photo taken 11/27/05.
A folded diamond interchange (Exit 15) joins I-238 with SR 185 (Mission Boulevard) to the immediate west of I-580 and Foothill Boulevard. Photo taken 11/27/05.
Exit 15 loops away from I-238 west to SR 185 (Mission Boulevard) at 170th Avenue in Ashland. Mission Boulevard leads SR 185 south to Hayward and north to Bayfair Center mall and San Leandro. Photo taken 11/27/05.
A confirming marker for Interstate 238 north precedes the bridges spanning BART commuter rail. Photo taken 12/27/01.
The succeeding exits from I-238 northbound depart over the next mile for I-880 (Nimitz Freeway) south and Springlake Drive in San Leandro. Photo taken 11/27/05.
A sweeping flyover ramp takes two lanes of traffic southward from I-238 to Interstate 880 (Admiral Nimitz Freeway) through San Lorenzo to California 92 and the San Mateo Bridge across San Francisco Bay. Photo taken 11/27/05.
Exit 16 separates from I-238 south for Interstate 880 south to Fremont and San Jose and California 92 (San Mateo Bridge) west to the Peninsula cities of San Mateo, Foster City and Belmont. Photo taken 11/27/05.
Exit 16B follows onto adjacent Springlake Drive to link I-238 with Hesparian Boulevard to unincorporated San Lorenzo. Photo taken 12/27/01.
The freeway mainline defaults onto Interstate 880 to Alameda and Oakland. Exit 17A separates ahead of the wye interchange with the Nimitz Freeway for Washington Avenue into San Leandro. Photo taken 12/27/01.
Interstate 238 scenes
2 photos
2 photos
Interstate 238 freeway entrance signs at the southbound on-ramp from Lewelling Boulevard in Ashland. Photos taken 12/27/01.



Photo Credits:

12/27/01, 11/27/05, 07/04/06, 03/27/17 by AARoads

Connect with:
Interstate 580
Interstate 880

Page Updated 06-19-2018.