bicycle/pedestrian overpass on the controlled-access portion of Central Expressway
County Route G6 (
CR G6) is a signed long, east–west route in the western portion of
Silicon Valley in
Santa Clara County, California, United States. It consists mainly of
Central Expressway, along with portions of
Alma Street in
Palo Alto and
De La Cruz Boulevard in
San Jose. While paralleling
US 101,
El Camino Real (
SR 82) and
I-280, all of which are signed north–south, Central Expressway is signed east–west. This is due to the fact that all of these routes move in an east–west direction in this area, but these other routes continue longer than Central Expressway and are mostly north–south overall. This route is part of the Santa Clara County expressway system.
Route description CR G6 actually begins in the west at
Oregon Expressway (CR G3) as Alma Street in
Palo Alto. In Palo Alto, CR G6 remains a major surface street with four lanes of traffic and a center turning lane to service the many driveways and turnoffs available. At the Palo Alto –
Mountain View border at San Antonio Road, CR G6's character changes, removing the driveways and frequent intersections and adding a center divider, and is known as Central Expressway. Central continues east as a 4-6 lane road through the city of Mountain View. There are signalized intersections at major thoroughfares, and there is a
grade crossing for the
VTA Light Rail. This section's intersections are primarily at-grade with cross streets controlled by
traffic lights, although there are some overpasses, such as for San Antonio Road, Shoreline Boulevard,
SR 85, Whisman Road,
SR 237, and Middlefield Road. Up to this point, the roadway has paralleled the
Caltrain rail line all the way from the
Palo Alto station, which limits the intersections on the south side of the road. The roadway branches off from the railway at Bernardo Avenue. After crossing under
SR 85, Central Expressway takes on a very freeway-like appearance (which is not typical for most county roads) for several miles through
Sunnyvale. Through this section, Central Expressway has a wide center divider with guardrails, and access is limited to a sequence of several separated grade interchanges at main cross streets with no turnoffs or driveways. The final in this sequence is at
Lawrence Expressway (CR G2). East of CR G2, Central resumes at grade intersections along with sporadic
HOV lanes at the approaches to intersections. Central has one final separated grade interchange with
San Tomas Expressway (CR G4). After CR G4, Central Expressway continues east for about a mile as a 6-lane expressway until it abruptly ends at De La Cruz Boulevrad, where all lanes must turn left or right. CR G6 continues for a few hundred feet north on De La Cruz until it reaches its terminus at
US 101, just outside the north end of the runways for
San Jose International Airport. The physical road continues as Trimble Road towards CR G4, while at its western terminus in Palo Alto, Alma Street continues northwest through downtown Palo Alto until Alma ends at El Camino Real near the border of Palo Alto and
Menlo Park. The posted speed limit on CR G6 is 50 MPH (80 km/h). In Mountain View, the posted limit drops to 45 MPH.
History Central Expressway was first designated in 1962. Central Expressway was a vital route through the western Silicon Valley in the days before
US 101 had been widened and
I-280 had been built as an alternate route. Central Expressway still acts as an alternate route to US 101 through the west valley, however usage has declined as both freeways are now much larger and more direct routes. In 1982, the prohibition against bicyclists using Central Expressway's shoulders was lifted. All pedestrian prohibitions were repealed by 2003. In 2007, construction was completed near the eastern terminus widening Central Expressway to accommodate an
HOV lane and a reconfiguration of the intersection with Lafayette Street. In 2016,
VTA expanded the Central Expressway grade crossing from 1 track to 2 tracks, necessitating some closures between Whisman and Mary for construction. CR G6 was also closed to vehicular traffic in the same stretch on the day of
Super Bowl 50 so that Light Rail traffic would have priority to
Levi's Stadium. In 2020, Mountain View closed Castro Street to vehicular traffic to support outdoor dining in the wake of the COVID-19 pandemic. The road is still closed to this day, and the turn pockets onto Castro Street from Central remain coned off while the city and county determine more permanent plans for this intersection. In early 2023, the eastern terminus of CR G6 was modified to match the new configuration of the De La Cruz Boulevard / US 101 interchange. The right slip ramps to/from De La Cruz on Central were permanently closed to traffic and replaced with standard right turn lanes. Central Expressway is currently signed as CR G6 sporadically along its entire length.
Major intersections ==G7==