Transportation issues related to construction of the proposed project include the effects of increased traffic generated by construction workers and construction vehicular activities, and the effects of construction operations on traffic flow (due to reduced travel width during construction work hours), on access to adjacent land uses for both general and emergency access, on transit service, on bicycle and pedestrian safety, and on on-street parking conditions. Information contained in the Proponent’s Environmental Assessment (PEA), prepared in October 1998 for the proposed project, and additional information provided by PG&E to the CPUC in a letter dated December 4, 1998, served as the bases for the following explanatory text.

  1. Long-term traffic impacts (i.e., increase in traffic or congestion) would not occur, as the proposed project would not generate trips or permanently alter any public roads. Occasional maintenance activities would briefly affect only local segments; this would be a less than significant impact. The duration of potentially significant traffic impacts would be limited to the period of construction activities. Therefore, mitigation measures incorporated into the proposed project (as identified in the PEA and later in this section) are focused on reducing the short-term project construction effects.

  2. Short-term increases in traffic resulting from construction activities would be expected. Traffic increases would be generated by the up to 20 construction workers arriving and leaving each day at each work site, trucks hauling excavated and backfilled materials associated with trench construction, and construction equipment. Project-generated traffic would be dispersed throughout the construction work hours, thus minimizing the effect on traffic flow on project area roadways. The primary impacts from construction truck traffic would be a temporary and intermittent reduction of roadway capacities due to slower movements and larger turning radii of the trucks compared to passenger vehicles, as well as traffic-related effects such as noise and vibration.

    During construction of the new overhead lines at and adjacent to the Monta Vista substation (on PG&E property), temporary road and lane closure would not be necessary. Surrounding roads are anticipated to accommodate the construction-related increase in worker trips and truck trips with less than significant effects.

    During construction of the approximately one mile of new line (on English Oak Way, Salem Avenue, Foothill Boulevard, Starling Drive, Baxter Avenue, Creston Drive, and Groveland Drive), temporary road and lane closure would be necessary. All of the roadways directly affected by underground construction are low- to moderate-volume local streets and minor collectors, with two travel lanes and parking permitted on both sides of the street, with the exception of Foothill Boulevard. The latter is a four-lane major collector that has a bike lane/route on both sides of the street and short intervals with on-street parking. Foothill Boulevard carries high traffic volumes during peak commute hours, providing primary access to Interstate 280 (I-280) from residential areas located in the western portions of the City of Cupertino. Foothill Boulevard also experiences heavy truck traffic associated with the Kaiser Cement Plant and the Stevens Creek Quarry (west of the Monta Vista substation) during non-commute hours.

    Construction of the proposed underground line would require a work zone width of 20 feet, thus reducing the available travel width on roads and causing short-term traffic delays for vehicles traveling past the construction zone. The pavement width on the two-lane roadways generally varies from 36 feet to 40 feet. Alternate one-way traffic control (with flaggers) would be conducted along all two-lane roadways, with the possible exception of Starling Drive. Despite the 60-foot width of Starling Drive, the tight radius of curve from Foothill Boulevard to Starling Drive causes space limitations that could create disruptive queues of vehicles on Foothill Boulevard. Traffic entering and exiting the Creston area at Foothill Boulevard may need to be rerouted to Vista Knoll Boulevard during work construction hours for a period of approximately two weeks. The City of Cupertino would be consulted during preparation of the traffic management plan (see mitigation measures below), to determine the best means to maintain traffic flow in this area. Use of Starling Drive by emergency vehicles would be maintained at all times. Because Foothill Boulevard is a divided road with two lanes on each side, simultaneous two-way traffic flow would be maintained during construction work hours.

    The typical lane closures on all roads in the project area would be a maximum of 600 feet in length and would follow traffic diversion plans as proscribed by encroachment permits that will be obtained from the City of Cupertino and Santa Clara County. Collectively, these lane closures are anticipated to last about six months.

    The temporary lane closures and increased traffic disruption in the project area would be a potential short-term impact of the project. Implementation of mitigation measures described below in this section would reduce this impact to a less than significant level.

    Construction of the project would cause disruptions to transit service. There are bus stops for the Santa Clara Valley Transit Authority (SCVTA) Routes 23 and 23A on Foothill Boulevard, to which access would be disrupted during days when the work zone is adjacent to the bus stop. Cupertino Unified School District and Fremont Unified High School District buses also stop in the project area. PG&E has consulted with SCVTA and the school districts, and continued coordination with these transit service providers would ensure that the impact would be less than significant.

  3. There are no proposed modifications to existing roadway configurations as a result of the proposed project. Construction-generated trucks on project area roadways would interact with other vehicles. Implementation of traffic control plans, with standard advance warning signs and delineation (e.g., traffic cones and pavement markings) would ensure safe and efficient traffic flow through the work zone. No impact related to traffic safety hazards from design features or from incompatible uses would occur.

  4. Construction of the proposed project would affect access to adjacent land uses and streets for both general and emergency traffic. Access to driveways and to cross streets along the construction route may be temporarily blocked due to trenching and paving. This would be an inconvenience to some and a significant problem for others, particularly emergency service providers (e.g., police and fire). Vehicle access would be restored at the end of each work day through the use of steel trench plates or trench backfilling. Emergency vehicles access would be maintained at all times throughout project construction. PG&E would coordinate any lane closures with emergency service providers. The duration of this short-term inconvenience would be a less than significant impact assuming sufficient advance notification of the timing of construction for affected properties.

  5. The proposed project would not generate long-term parking demand because operation of the facilities would not require additional staff. Project construction would require parking for workers, but this could be accommodated with existing parking spaces in nearby areas. During underground construction along Foothill Boulevard, parking would not be permitted between Salem Avenue and Starling Drive. Parking also would be restricted temporarily on English Oak Way, Salem Avenue, Starling Drive, Baxter Avenue, Creston Drive, and Groveland Drive during construction of the underground line in those streets. Parking utilization is low in this area (typical of on-street parking occupancy in residential areas with garages), and parking would remain available on adjacent streets. The impact on parking conditions would be less than significant.

  6. The sidewalk and wheelchair ramps along the east side of Foothill Boulevard would remain open during trenching along the street. Because the bike lane would be closed for up to 600 feet during construction on Foothill Boulevard, bicyclists would be allowed to use the eastside sidewalk along the portion of affected road. The bike lane on the west side of Foothill Boulevard would remain open. The sidewalk on the south side of Salem Avenue also might be temporarily closed; however, the sidewalk on the north side would remain open. Wheelchair ramps to sidewalks on the south side of Salem Avenue could be temporarily blocked by construction activities. These closures would be temporary and kept to a minimum. At no time would both sidewalks on any street along the project route be closed. Impacts to pedestrian and bicyclist traffic would be temporary and less than significant; mitigation measures outlined below in this section would further reduce the impact.

  7. The short-term construction of the project would not conflict with policies supporting alternative transportation. Once the line is installed, the affected facilities would return to their current status, with only occasional maintenance activities briefly affecting local segments. No project impact would occur.

  8. Union Pacific Railroad owns a railroad track that runs from Kaiser Cement Plant through the Monta Vista substation, under Foothill Boulevard, and adjacent to I-280 until reaching the I-280/State Route 85 interchange. The project would cross this track at two points, overhead at the Monta Vista substation site, and underground (by means of horizontal drilling) between the end of Groveland Drive and I-280. Union Pacific Railroad operates one freight train daily on this track. Project construction would not affect railroad operations. No waterborne or air traffic facility is located near the project work areas.

Applicant Proposed Mitigation

The following mitigation measures proposed by PG&E would ensure that all impacts to transportation and traffic resulting from the project would be less than significant:

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