County Route G4 (California)

Infobox road
state=CA
type=CR
route=G4
marker_

alternate_name=San Tomas Expressway, Montague Expressway
maint=Santa Clara County Expressway System


length_mi=14.5
length_round=0
length_ref=
established=1962
direction_a=West
terminus_a=jct|state=CA|SR|17 in Campbell
junction=jct|state=CA|I|280 in San Jose
jct|state=CA|SR|82 in Santa Clara
jct|state=CA|CR|G6|county1=Santa Clara in Santa Clara
jct|state=CA|US|101 in Santa Clara
jct|state=CA|I|880 in San Jose
direction_b=East
terminus_b=jct|state=CA|I|680 in San Jose

County Route G4, more commonly referred to as San Tomas Expressway and Montague Expressway is a busy 14.5 mile (23 km) long link across Silicon Valley. G4 is part of the Santa Clara County Expressway System.

Route summary

G4 begins in the south at its interchange with SR 17 and Camden Avenue as San Tomas Expressway in the city of Campbell. The road is three lanes wide in each direction, with an HOV carpool lane occupying the right lane, from SR 17 north to El Camino Real (SR 82), where it expands to four lanes in each direction with an HOV lane until San Tomas "ends" at US 101. The majority of intersections along San Tomas are at grade controlled by traffic lights, however access is limited to these intersections only (there are no driveways etc with access to the expressway). The only separated grade intersections along San Tomas are at SR 17, US 101, Winchester, and the junction with Central Expressway (G6). G4 intersects at grade with El Camino Real in Santa Clara. Further north in Santa Clara, G4 crosses US 101 and becomes Montague Expressway.

Montague Expressway is signed as an east-west route, however it is not signed as G4 along its entire length. Montague continues east as an 8 lane road until it crosses Interstate 880 on the San Jose/Milpitas city line, where it loses a lane to become a 6 lane road. G4 reaches its eastern terminus at Interstate 680 but the physical road continues as Landess Ave. further east until it ends at its intersection with Piedmont Road.

History and legislative status

G4 was designated and signed in 1962 along the San Tomas portions. Montague was designated later around 1978. Whether this has anything to do with Montague not being physically signed as G4 is uncertain. Emergency Call boxes along Montague however are labeled as being on G4 leaving no doubt that Montague is part of G4.

Original plans called for G4 to originate at present day G21's junction with US 101, then head north via present day Capitol Expressway, Hillsdale Avenue, and Camden Avenue where it would have met the present day southern terminus. These plans were never brought to fruition.

From SR 82 south to Interstate 280, G4 is an unsigned part of the Juan Bautista De Anza National Historic Trail which follows the route Juan Bautista de Anza took leading his expedition into California from Mexico in 1775-76 (note: to continue north on the trail you must utilize Saratoga Avenue to access I-280 as G4 has no interchange with the interstate).

Landmarks and points of interest

* Intel Headquarters & Museum (just east of US 101)
* The Great Mall of the Bay Area (controversial mall when constructed)
* Sun Microsystems headquarters (at Agnew Road in Santa Clara)
* NVIDIA headquarters (at Walsh Road in Santa Clara)

Major cities

*Campbell, California
*San Jose, California
*Santa Clara, California
*Milpitas, California

ee also

*List of California County Routes