California county routes in zone G
There are 21 routes assigned to the "G" zone of the California Route Marker Program, which designates county routes in California. The "G" zone includes county highways in Monterey, San Benito, San Luis Obispo, Santa Clara, and Santa Cruz counties.
G1
County Route G1 is a road in San Benito County, California, United States, providing access to Fremont Peak State Park from State Route 156 in San Juan Bautista. It is signed as San Juan Canyon Road for almost the entire length except for a small portion of The Alameda.Route description
Though some maps mark G1 as extending about from Fremont Peak State Park's main parking lot to State Route 156, officially the county route is only from near its intersection with Hillside Drive.From the southern end on Fremont Peak as San Juan Canyon Road, the road begins a steep, sharp-curved winding descent from around for the first, north to northeast. G1 then curves to the west for about before turning north; the G1 designation officially begins in this westbound segment at a point near its intersection with Hillside Drive. At the intersection of Mission Vineyard Road, G1 becomes The Alameda, which then heads north for approximately before reaching the northern terminus at State Route 156. Beyond the northern terminus, The Alameda continues into downtown San Juan Bautista for until the intersection of First Street.
Major intersections
G2
County Route G2, more commonly known as Lawrence Expressway and Quito Road, is a busy long north-south link through Silicon Valley in Northern California. The majority of G2 is part of the Santa Clara County expressway system.Route description
G2 runs from the Quito Road overcrossing of SR 85 in Saratoga, north along Quito Road. G2 is not signed along this section and is not commonly recognized as existing along this 2 lane road by either locals or mapmakers. The Quito Road portion is also maintained by the City of Saratoga rather than Santa Clara County.As the road leaves Saratoga and enters San Jose, it widens to a 6 lane county-maintained expressway with a concrete island divider; at this point it becomes Lawrence Expressway. The Lawrence Expressway section from just south of Saratoga Avenue is more readily recognized as G2. Local residents almost exclusively refer to G2 as Lawrence Expressway. The road continues north, with access usually restricted to major intersections which are controlled via traffic lights.
Lawrence Expressway continues northeasterly and intersects with I-280 and Stevens Creek Boulevard over a complex shared separated grade crossing: the expressway proceeds under I-280 before immediately rising over Stevens Creek Boulevard. San Tomas Expressway and Campbell Avenue also share ramps for access to I-280 with the exception of the onramp to Southbound I-280 which is accessed directly from Lawrence Expressway. Lawrence Expressway continues north into Santa Clara and widens to 8 lanes with an HOV lane occupying the far right lane.
Lawrence Expressway also has another separated grade interchange with El Camino Real. It then enters Sunnyvale. At this point the expressway passes over Caltrain's Lawrence Station. It also passes under Central Expressway on a separated grade interchange and over US 101 on a separated grade interchange. The US 101 interchange was upgraded in the early 2000s to include traffic light control on G2.
G2 reaches its northern terminus at the end of Lawrence Expressway at the SR 237 Freeway. The physical road continues north as Caribbean Drive, which then curves back south through Sunnyvale and Cupertino, paralleling Lawrence Expressway under several different street names until the roads intersect again at Highway 9 and Quito. This effectively makes the road one continuous counterclockwise loop through the Santa Clara Valley, where one driver could start on Quito Road and end up exactly where they started without ever changing lanes.
History
The designation G2 existed to the 1950s. The route replaced what was originally called Lawrence Station Road, from Mountain View–Alviso Road in the north to Stevens Creek Blvd. on the south, roughly paralleling Saratoga Creek. Lawrence Station was itself named for Alfred Chester Lawrence. Crossing Stevens Creek, the route was originally called Doyle Road, a small two lane road up to the point the current Doyle Road exits to the east. The section between Doyle and Saratoga Avenue at Quito Road was originally orchards.G2 was first signed as a Santa Clara County Route in 1962 as construction was completing on sections of the upgrade to an expressway. County Route G2 was originally planned to link up with SR 85 when it was built. At the time of G2's inception SR 85 was in the early planning stages and an interchange had been envisioned at Quito Road. However, opposition to the freeway was intense in Saratoga and the planned interchange between SR 85 and G2 along with an interchange further north at Prospect Road were abandoned in favor of the existing Saratoga Avenue interchange. G2 is unsigned from SR 85 to Saratoga Avenue along Quito Road. North of Saratoga Avenue, Lawrence Expressway is currently signed as G2.
In the 1990s Lawrence Expressway was widened north of I-280 to 8 lanes to accommodate an HOV carpool lane.
As of 2019, Santa Clara County is planning a major grade separation project at Homestead Road. This will be one of the largest expressway improvement projects in many years.
Major intersections
G3
County Route G3, more commonly known as Page Mill Road and Oregon Expressway, is a short northeast–southwest arterial route that spans the lower peninsula region of the San Francisco Bay Area from I-280 to US 101. G3 runs through Palo Alto and unincorporated Stanford University lands. It is part of the Santa Clara County expressway system.Route description
CR G3 begins in the west at its interchange with I-280, at the Los Altos Hills–Stanford border. It proceeds northeast as a four lane expressway over the rolling hills of Stanford University until it reaches Foothill Expressway, at which it has an at-grade intersection. East of Foothill Expressway, G3 descends down into the more urban areas of the lower peninsula, going through the industrialized area of the Stanford Research Park located in Palo Alto. The road along this section has a reduced speed limit and several turnoffs along its length until it reaches El Camino Real.After SR 82, G3 branches from Page Mill Road, and curves under the Caltrain tracks, continuing as Oregon Expressway for the remainder of its northeastward journey. Oregon Expressway functions more comparably to a County-maintained Arterial Road for Palo Alto, with frequent signaled intersections and a posted speed limit of 35 MPH. G3 reaches its eastern terminus at its junction with US 101, where it shares an interchange with Embarcadero Road.
Page Mill Road continues southwest of I-280 for, a twisting two-lane road that climbs to Skyline Boulevard at the crest of the Santa Cruz Mountains. It passes the entrance to Palo Alto's Foothills Park, and the Monte Bello and Los Trancos Open Space Preserves. Under the name West Alpine Road, the road descends west of Skyline Boulevard to a turn-off that leads to Portola Redwoods State Park, where the original Page sawmill was located. Other than a commemorative sign, no artifacts remain at the mill site, which is accessible only by Slate Creek Trail from either Portola Redwoods state park or from Skyline Boulevard.
History
This route was designated in 1962. G3 is currently signed its entire length. Page Mill Road was originally known as Mayfield–Pescadero Road, but only the urbanized portion of Page Mill Road is part of G3.The widening of Oregon Avenue from a congested narrow residential street to a median-divided 4-lane Oregon Expressway was narrowly approved by Palo Alto voters in a June 5, 1962, election; about 90 homes on the south side of Oregon Avenue were moved or destroyed to make room for it. The original Oregon Ave still exists on the north side of the roadway, though is mostly separated from G3 with trees and shrubbery.
Due to the steep grade and high water table around the area of the Caltrain underpass, the underpass is notorious for flooding during heavy rains, which often overwhelmed the county pumps which were installed due to the existence of a Superfund site 1/4 mile upstream on Page Mill road. When the underpass is closed due to flooding, through traffic must detour onto Alma Street and cross the train tracks at either Churchill Ave to the North, or Charleston Rd to the south.
When Interstate 280 was completed through the area in 1969, the old narrow Page Mill road, which passed by the Frenchman's Tower, was bypassed over the hills to the south and expanded to 5 lanes from 2. The old road was renamed "Old Page Mill Road", the center line was removed, and car access was limited to eastbound and local traffic only. The road is still traversable today and is a popular route for bicyclists.
In 2014, the county began a rehabilitation project on Oregon Expressway, which entailed rebuilding and landscaping of the center median, installation of new traffic lights and mast arms, and repaving of the travel lanes. The intersection of Ross and Oregon, previously an uncontrolled intersection, had new traffic signals and sensors installed and Ross was converted into a Bike Boulevard.
Major intersections
G4
County Route G4, more commonly referred to as San Tomas Expressway and Montague Expressway is a busy long link across Silicon Valley. G4 is part of the Santa Clara County expressway system.Route description
CR 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 Homestead Road, 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. The only grade-separated intersections along San Tomas are at SR 17, US 101, Winchester, and the junction with Central Expressway. 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.