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County Route Shield

Santa Clara
County Sign Route G4

[Click here for a key to the symbols used. Some county routes were constructed with federal funds. These routes are indicated as FAP (Federal Aid Primary), FAU (Federal Aid Urban), or FAS (Federal Aid Secondary). If no funding source is shown, no federal funds were used. Note that while some segments seem to have the same attributes, they may differ in the county-local road number assigned to the segment, or in the Caltrans Map Sheet number.]

Routing Routing

  1. Cty Rte G4 - San Tomas / Montague ExpwySan Tomas Expressway in Campbell from Route 17 to the San Jose city limits (FAU, 2.22 mi)

  2. San Tomas Expressway in San Jose from the San Jose city limits to Stevens Creek Blvd (FAU, 1.83 mi)

  3. San Tomas Expressway from Stevens Creek Blvd to the Santa Clara city limits (FAU, 0.15 mi).

    Note: This segment makes no sense, as Stevens Creek Blvd is the Santa Clara city limit. Perhaps there was a post-1976 annexation.

  4. San Tomas Expressway in Santa Clara from the Santa Clara city limits to US 101 (FAU, 4.10 mi)

    Status Status

    In June 2016, it was reported that there are plans to widen the expressway from south of Homestead Road to El Camino Real. Plans include:

    • Widening of the expressway from three to four lanes in each direction, from El Camino through Homestead, merging back to three lanes south of Homestead Road.
    • Extending the San Tomas Aquino trail on the west side heading south from El Camino, crossing Benton and ending at Homestead. A sidewalk will be installed along the east side of the expressway.
    • Adjacent to the new trail and sidewalk, installing 10-foot-high walls to replace the existing 6-foot-high walls.
    • Making improvements to both the intersection and traffic signals at Benton and Homestead, including adding double left-turn lanes on Homestead.

    The carpool lane may be temporarily closed.
    (Source: Mercury News, 6/14/2016)

    In September 2019, it was reported that Santa Clara County plans to turn off the electronic signs and beacons that were installed decades ago to indicate carpool lane operation, and remove them. The county will rely on the black-and-white carpool signs already installed that show the carpool hours. The yellow flashing lights were put in place to provide drivers extra warning.
    (Source: �� Mercury News, 9/16/2019)

  5. Montague Expressway in Santa Clara from US 101 to the Guadalupe River (FAU, 1.62 mi)

  6. Montague Expressway from the Guadalupe River to the San Jose city limits (FAU, 0.76 mi).

    Note: This segment makes no sense, as the Guadalupe River is the San Jose city limit. Perhaps there was an annexation of Santa Clara county land post-1976 with either Alviso, Barryesa, or North San Jose.

  7. Montague Expressway in San Jose from the San Jose city limits to the Milpitas city limits (FAU, 2.10 mi)

  8. Montague Expressway in Milpitas from the Milpitas city limits to I-680 (FAU, 1.33 mi)

    Status Status

    It was reported in October 2016 that South Milpitas Boulevard will be completely closed from Montague to Garden Street for five weeks beginning Oct. 14, 2016 for a big water project that will also widen and raise Montague to accommodate the flood control measures and fill the carpool lane gap.
    (Source: SJ Mercury News, 10/3/2016)

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History and Signage Information History and Signage Information

The San Tomas Expressway portions were defined in 1962. The Montague Expressway portions were defined in 1978. Apparently, County Sign Route G4 continued along Hillsdale Avenue, and Capitol Expressway in San Jose. Capitol Expressway is now County Sign Route G21.

Naming Naming

Expressways were most often named for the older roads they were built over, such as Almaden, Capitol, Lawrence, Oregon, Page Mill and Montague. As the expressways expanded they kept their name. For Montague Expressway in Santa Clara and proceeding through San Jose to Milpitas, the alignments used were Montague Road, Trimble Road and Landess Avenue. The big sweeping curves on Montague are the connecting transitions from one alignment to the other. Montague Road ran from Lafayette Street to North First Street. There used to be property, including a large Victorian home, owned by W.W. Montague. The company still exists under the Montague name and specializes in restaurant-quality stoves and ranges. Apparently Montague lived on the south side of the road and the Lick Mansion is on the north off Lick Mill Boulevard. Though they looked somewhat alike, do not confuse them. The Montague residence no longer exists. W.W. Montague was a rancher and a San Francisco postmaster who also manufactured coal and wood-burning stoves.
(Source: SJ Mercury News 3/10/2015; City of Santa Clara)

Status Status

The San Tomas Expressway portions are signed. Montague Expressway is unsigned. Total mileage for both expressways: 14.11 mi.

The SAFETEA-LU act, enacted in August 2005 as the reauthorization of TEA-21, provided the following expenditures on or near this route:

Commuter Lanes Commuter Lanes

Montague Expressway: from Interstate 680 in Milpitas to Route 101 in Santa Clara. Lanes also run on San Tomas Expressway from Central Expressway in Santa Clara to Winchester Blvd in Campbell. These lanes were added in 1982.

Acronyms and Explanations:

Back Arrow CR G3 Forward Arrow CR G5

© 1996-2020 Daniel P. Faigin.
Maintained by: Daniel P. Faigin <>.