the purpose of this visual impact assessment (via) is to document potential visual...

VISUAL IMPACT ASSESSMENT

Mathilda Avenue Improvements at SR 237 and US 101 Project

May 2016

California Department of Transportation District 4, Santa Clara County, SR 237 and US 101

SR 237 PM 2. 7 /3.3 US 101 PM 45.2/45.8

EA 04-4H2900

Prepared by: ----+-\-+--. _~ __ c...\c._ _____ Date: May 13,2016 e Jennifer Stock

Approved by:

Project Landscape Architect ICF International

CA License# 5155

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j Ki berly White Branch Chief, Design A

CA License# 4683 (510) 286-6370

Caltrans, District 4

Statement of Compliance: Produced in compliance with California Environmental Quality Act (CEQA) requirements, as appropriate, to meet the level of analysis and documentation that has been determined necessary for this project.

Visual Impact Assessment for Mathilda Avenue Improvements at SR 237 and US 101 Page 1

VISUAL IMPACT ASSESSMENT Mathilda Avenue Improvements at SR 237 and US 101 Project

PURPOSE OF STUDY AND ASSESSMENT METHOD The purpose of this visual impact assessment (VIA) is to document potential visual impacts caused by the Mathilda Avenue Improvements at State Route 237 (SR 237) and United States Highway (US 101) project (project) and propose measures to lessen any detrimental impacts that are identified. Visual impacts are demonstrated by identifying visual resources in the project area, measuring the amount of change that would occur as a result of the project, and predicting how the affected public would respond to or perceive those changes. This VIA follows the guidance outlined in Visual Impact Assessment for Highway Projects, published by the Federal Highway Administration (FHWA) in March 1988.

PROJECT DESCRIPTION The project is proposing to improve Mathilda Avenue in the City of Sunnyvale from Almanor Ave-nue/Ahwanee Avenue to Innovation Way, including on- and off-ramp improvements at SR 237/Mathilda Avenue and US 101/Mathilda Avenue interchanges. On SR 237, the project limits are from 0.3 miles east of the US 101/SR 237 interchange (post mile [PM] 2.7) to 0.3 miles east of the Mathilda Avenue under-crossing (PM 3.3). On US 101, the project limits are from 0.5 miles south of Mathilda Avenue overcrossing (PM 45.2) to 0.3 miles south of SR 237/US 101 interchange (PM 45.8). The total length of the project on Mathilda Avenue is approximately one (1) mile. Figure 1 shows the location of the project. The project alternatives include Build Alternative 1, Build Alternative 2, and the No-Build Alternative. The design features of the two Build Alternatives (Figures 2a and 2b) include reconfiguration of the US 101/Mathilda Avenue and SR 237/Mathilda Avenue interchanges. The Build Alternatives include design variations for reconfigured roadways and intersections, and construction of new signalized intersections. Proposed improvements included in the Build Alternatives south of Ross Drive on Mathilda Avenue and at the US 101 interchange are identical. This includes new bicycle and pedestrian facilities, utility reloca-tions, new storm water treatment facilities, enhanced lighting, ramp metering modifications, modification of overhead signage, and a new retaining wall. In addition to the improvements listed above, Build Alter-native 2 includes construction of a diverging diamond interchange (DDI)1 north of Ross Drive on Mathilda Avenue (Figure 3).

The Build Alternatives would consist of the following roadway improvements:

Provide three continuous through lanes in each direction of Mathilda Avenue.

Remove northbound US 101 loop off-ramp and shift traffic to northbound US 101 diagonal off-ramp.

1 A diverging diamond interchange (DDI), also called a double crossover diamond interchange (DCD) is a type of diamond inter-change where traffic briefly crosses over to the left (opposite) side of the roadway, guided by traffic signals at each crossover. This allows vehicles to turn left onto freeway on-ramps without stopping and without conflicting with through traffic. The signals at ramp terminal intersections can be operated with two signal phases (phases when a traffic signal allows for traffic at an inter-section to cycle through specific movements for each direction) instead of three.


Realign and widen northbound US 101 ramps and signalize ramp intersection with Mathilda Avenue, and construct left-turn lane on southbound Mathilda Avenue to access northbound US Highway 101 loop on-ramp.

Realign southbound US 101 off-ramp and loop on-ramp, and signalize ramp intersection with Mathilda Avenue.

Modify Mathilda Avenue / Ross Drive signal intersection.

Close Moffett Park Drive between Bordeaux Drive and Mathilda Avenue, replace with a Class I bikeway (as described below), and shift traffic to Bordeaux Drive and Innovation Way.

Remove westbound SR 237 ramp signal intersection. Realign westbound SR 237 off-ramp op-posite Moffett Park Drive and modify signal intersection.

Build Alternative 1 would modify westbound SR 237 ramps to provide a diamond configura-tion.

Build Alternative 2 would modify Mathilda Avenue and SR 237 ramps to provide a DDI config-uration. Eastbound Moffett Park Drive between Innovation Way and Mathilda Avenue would be diverted to Innovation Way to access Mathilda Avenue.

Enhanced bicycle and pedestrian facilities would be provided. Bicycle improvements on Mathilda Avenue would consist of both Class II and Class III bikeways, based on available pavement widths within the project limits, and would connect to the existing Class III bikeway north of Innovation Way and Class I bikeway on the Sunnyvale West Channel. Bicycle improvements on Moffett Park Drive would consist of a Class I bikeway between Bordeaux Drive and Mathilda Avenue. Between Mathilda Avenue and Innovation Way, Class II and Class III bikeways would be considered based on available pavement widths within the project limits. A continuous sidewalk would be provided on the east side of Mathilda Avenue within the project limits with crosswalks, curb ramps, and pedestrian countdown signals at each intersection. The new cross-walks at the reconfigured ramp intersections would be signalized. In addition, both Build Alternatives would provide replacement planting within the US 101 and SR 237 interchanges with Mathilda Avenue and along Mathilda Avenue within the project limits. Under the No-Build Alternative, no changes would be made to the existing local roadways or freeway system within the project limits.

PROJECT LOCATION AND SETTING The project location and setting provides the context for determining the type and severity of changes to the existing visual environment. The project is located on Mathilda Avenue, generally between Innovation Way and Almanor Avenue, in the City of Sunnyvale, California. The project is located in the Central Coast biogeographic province, just south of the southern portion of San Francisco Bay (Bay) and the associated Baylands. The project vicinity consists of South Bay urban development, Bay waters, and the Baylands’ salt evaporation ponds, salt marshes, and wetlands. The Baylands provide relatively flat open expanses of natural wetland features that have both sinuous and geometric shapes and earth-toned colors that pro-vide an undeveloped, more natural visual contrast to the nearby, densely populated urban area that is characteristic of the project corridor. The project corridor is defined as the area of land that is visible from, adjacent to, and outside the highway Right of Way (ROW), and is determined by topography, vegetation, and viewing distance. The project corridor is generally flat, except at the highway interchanges that are built up to accommodate the grade-separated crossing of SR 237 over Mathilda Avenue and the crossing of Mathilda Avenue over US 101. Land uses primarily include hotels and office complexes located on either side of Mathilda Avenue; single-

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family and multi-family residences located east of Mathilda Avenue; and major and minor transportation facilities associated with SR 237, US 101, Mathilda Avenue, and adjoining local roadways and associated signage. The Sunnyvale General Plan Community Character – Design Element identifies that SR 237, US 101, and Mathilda Avenue at US 101 are City gateways that could be improved through the use of special landscaping, signage, patterned pavement, and monuments or artwork (City of Sunnyvale 2011: 4-4). Ma-ture trees and shrubs are present within two median plantings, plantings within interchange loops, and roadside landscaping associated with businesses and residential areas to provide visual buffering from Mathilda Avenue, SR 237, and US 101. While not scenic vistas, the wide corridors of Mathilda Avenue, SR 237, US 101 and the elevated SR 237/Mathilda Avenue and Mathilda Avenue/US 101 overcrossings allow for scenic background views of the Diablo Range to the northeast and the Santa Cruz Mountains to the southwest. Vista views are not available due to buildings, infrastructure, and mature trees that intervene within potential vista views. There is no roadway within or near the project area that is designated in federal, State, or local plans as a scenic highway or route worthy of protection for maintaining and enhancing scenic viewsheds (Caltrans 2016, City of Sunnyvale 2011). US 101 is classified by Caltrans as a Landscaped Freeway between PM 45.57 and 47.14 (Caltrans 2014a). Along US 101, this designation begins approximately at the gore of northbound Mathilda Avenue exit ramp and continues north past the project limits on US 101. As defined by the Outdoor Advertising Act, a landscaped freeway “means a section or sections of a freeway that is now, or hereafter may be, improved by the planting at least on one side or on the median of the freeway ROW of lawns, trees, shrubs, flowers, or other ornamental vegetation requiring reasonable maintenance.” Landscaped freeways must have planting areas that are at least 1,000 feet in length that are in healthy condition and improve the aesthetic appearance of the highway. Functional plantings (i.e., plantings for erosion control, traffic safety, reduc-tion of fire hazards, and traffic noise abatement, or other non–ornamental purposes) do not qualify. The placement of advertising is prohibited within 660 feet of the edge of the ROW of a landscaped freeway. (Caltrans 2014b.) The project corridor is well-lit from street lighting along Mathilda Avenue and at the SR 237 and US 101 interchanges, safety lighting in parking lots, and interior and exterior building lighting associated with residences and businesses.

VISUAL RESOURCES AND RESOURCE CHANGE Visual resources of the project setting are defined and identified below by assessing visual character and visual quality in the project corridor. Resource change is assessed by evaluating the visual character and the visual quality of the visual resources that comprise the project corridor before and after the construc-tion of the project. The visual character of the project would be compatible with the existing visual character of the corridor. The project and its Build Alternatives would reconfigure the SR 237 and US 101 interchange ramps and reconfigure Mathilda Avenue to accommodate new signalized intersections and left-turn lanes. To accom-modate this, mature trees and shrubs would be removed at the median planting between Stations2 47+00 to 51+00 and 64+00 to 68+00 on Mathilda Avenue, within the SR 237 and US 101 interchange loops to accommodate the shifted ramps, west of Mathilda Avenue to accommodate a new retaining wall between

2 Refer to Figures 2 and 3a for stationing.


Stations 46+00 and 49+50, and east of Mathilda Avenue between Stations 49+00 and 56+00 to accommo-date new lanes for the SR 237 onramp and right hand turns onto Ross Drive. These changes would impact the views from nearby property owners and views from the roadway corridor. However, most of the areas with existing landscaping that would be disturbed during construction would receive replacement plant-ings to restore the aesthetic qualities that such landscaping provides. In addition, new landscape plantings would occur where paved portions of ramps are removed to accommodate the reconfigurations, improv-ing aesthetics; the reconfigured ramps would not greatly alter the appearance of the SR 237 and US 101 interchanges with Mathilda Avenue. Therefore, the visual character of the corridor and land adjacent to the ROW would not be greatly altered. Signalized intersections, bicycle and pedestrian facilities, street lighting, ramp metering, signage, and light rail crossing facilities are all existing elements associated with the project corridor and changes associated with these features would be implemented in a manner that maintains the existing visual character. Similarly, modifications to existing retaining walls and sound walls would be consistent with existing conditions and would not greatly alter views associated with the corri-dor. The visual quality of the existing corridor would be slightly altered by the project. Generally, the corridor would be slightly wider, but would retain its form, line, color, and texture in a manner that is consistent with existing conditions. Views from the project corridor to the surrounding landscape would be much the same because the Build Alternatives would only result in minor changes along the existing corridor to accommodate the project and landscaping would be replaced, retaining the existing vividness, intactness, and unity. Views of the Diablo Range and Santa Cruz Mountains would not be altered. Views of the project corridor from neighbors and from the roadway corridor would be slightly altered in a manner that would result in a slight reduction in the overall visual quality, largely due to vegetation removal. While these areas would be landscaped as part of the project, it would take several years for the vegetation to mature. As a result, Resource Change (changes to visual resources as measured by changes in visual character and visual quality) would be moderate-low.

VIEWERS AND VIEWER RESPONSE Neighbors (people with views to the road) and roadway users (people with views from the road) will be affected by the project. Neighbors consist of employees and patrons at nearby businesses and residents that immediately border the project corridor. Neighbors also include roadway users connecting to the project corridor from local roadways. Business occupants and residents are considered to have high visual sensitivity because while they are accustomed to views of the existing roadways and passing traffic, they generally view the project site for an extended period. Therefore, business occupants and residents are likely to have a high sense of ownership over local views, and are more likely to be affected by changes in the views from their businesses or homes than the visiting, business patrons or those passing by the site on local roadways. Business patrons are more focused on visiting businesses than on the project corridor and they have intermittent and limited views of the project corridor. Therefore, business patrons are likely to have moderate-low visual sensitivity. Roadway users include local commuters traveling to and from work, shoppers, recreational travelers, and commercial vehicles on Mathilda Avenue, SR 237, US 101, Moffett Park Drive, Bordeaux Drive, and Inno-vation Way. Roadway users travel at speeds ranging from a stop to approaching 75 miles per hour (the posted speed limit is 65 miles per hour) on SR 237 and US 101, 55 miles per hour (the posted speed limit is 45 miles per hour) on Mathilda Avenue, 55 miles per hour (the posted speed limit is 45 miles per hour) on Bordeaux Drive, and 35 miles per hour (the posted speed limit is 25 miles per hour) on Innovation Way.


Depending on speed, drivers and passengers are able to take in brief to longer views of the scenery around them. Most views from the project corridor are of surrounding development; however, sections of the roadway provide for more scenic views of a vegetated roadway corridor with views to the hillsides and mountains in the background. Therefore, roadway users are considered to have moderate visual sensitiv-ity. Public scoping comments generally focus on providing feedback and questions on specific elements of the project, such as bicycle and pedestrian safety considerations. The public comments did not express op-position to the project. Therefore, while not specifically stated, the responses tend to indicate general public support of improving the project corridor. Therefore, it is anticipated that the average response of all viewer groups will be moderate due to viewer group sensitivities and public interest surrounding the project.

VISUAL IMPACT Visual impacts are determined by assessing changes to the visual resources and predicting viewer re-sponse to those changes. As discussed above in Project Location and Setting, there are no officially desig-nated scenic roadways within or near the project corridor. In addition, scenic vista views are not available from the corridors of Mathilda Avenue, SR 237, and US 101 at the project site due to buildings, infrastruc-ture, and mature trees that intervene within these potential vista views. Therefore, implementation of the project would not damage scenic resources, such as trees, rock outcroppings, and historic buildings along a scenic highway or scenic vistas. Impacts to visual resources resulting from changes to the existing visual character and quality of the site and changes in light and glare are discussed below.

Build Alternatives As described in the Project Description, Build Alternatives 1 and 2 have the same footprint for the US 101 interchange with Mathilda Avenue, and the same roadway cross section between the US 101/Mathilda Avenue interchange and Ross Drive, the Moffett Park Drive connection to Bordeaux Drive, and between the Sheraton Sunnyvale parking lot entrance on Mathilda Avenue and the Innovation Way extension to Mathilda Avenue. These changes would look the same under both Build Alternatives. The primary differ-ence is that Build Alternative 1 would have a diamond configuration while Build Alternative 2 would have a DDI configuration. Both of these configurations would have a similar visual character and would result in similar impacts to existing features within the project corridor. Because the Build Alternatives would be visually similar, temporary and permanent impacts are discussed together below. Simulations for key ob-servation points (KOPs) were used to evaluate project impacts. The KOPs are mapped on Figure 4 and the simulations are provided in Figure 5 to Figure 7.

Temporary Impacts – Build Alternatives 1 and 2 General construction activities, construction staging/stockpiling, the storage of road-widening/building materials, the presence of construction equipment, and temporary traffic barricades would result in tem-porary construction impacts by altering the composition of the view available from and to the project corridor. Under both Build Alternatives, the greatest focus of visible activities associated with construction would be on roadway and ramp modifications. Other visible activities occurring during construction under both Build Alternatives, which have the potential to result in visual impacts are described in more detail under Permanent Impacts – Build Alternatives 1 and 2, and include the removal of mature landscaping including trees, shrubs, and/ or vines; replacement of the sound wall between Weddell Drive and the northbound US 101 off-ramp; the installation of the new retaining wall that would be located within ex-isting state ROW on the west side of Mathilda Avenue north of the existing northbound US 101 loop off-


ramp; the modification of the local roadway intersection connections and driveway entrances to Mathilda Avenues; the relocation of utilities; the modification and installation of lighting, ramp metering, and over-head signage; and the enhancement of bicycle and pedestrian facilities. During construction, these activ-ities would be seen as a continuation of construction activities associated with roadway and ramp im-provements and would only result in minor visual changes as the modifications are occurring. In addition, construction staging areas would be temporarily visible within the US 101 interchange with Mathilda Av-enue and between the westbound SR 237 ramps and Moffett Park Drive, where some trees and shrubs would be affected to accommodate staging. Individuals most affected by construction would be single-family residences along Weddell Drive and Per-sian Drive and multi-family residences along Weddell Drive. Single-family residences along Weddell Drive and Persian Drive face Bradford Drive. Privacy fences and Weddell Drive and Bradford Drive separate their back yards from Mathilda Avenue. These residents would experience visually disruptive construction ac-tivities within close proximity to their homes. Construction occurring north of SR 237 would not greatly affect businesses in this area because there has been and continues to be a great deal of construction occurring within this area due to its redevelopment, and existing businesses would be accustomed to seeing construction activities. Construction activities would be visible from SR 237 and US 101, but road-way users would pass by the Mathilda Avenue interchanges very quickly and would have only brief, pass-ing views lasting a few seconds at normal highway speeds. Businesses located west of Mathilda Avenue, off of Hamlin Court, would have extremely limited views of construction associated with vegetation re-moval to install a new retaining wall. The majority of construction activities would be visible to roadway users on Mathilda Avenue, where the bulk of construction would take place. Specific equipment that would be used for construction includes graders, excavators, pavers, compactors, and various types of construction vehicles. In general, the visual presence of construction activities is considered temporary because the project would take 12 months to construct. Temporary visual changes from construction sig-naling, signage, and lighting would occur, though they are not considered to be adverse. Nighttime con-struction would likely occur and some nighttime lighting at the construction site would be required and could result in nuisance light if not properly designed. Avoidance, Minimization, and/or Mitigation Meas-ure, Minimize Fugitive Light from Portable Sources Used for Construction, would ensure that lighting used for construction would be directed downward and that spill light would be minimized to the greatest extent possible.

Permanent Impacts – Build Alternatives 1 and 2 There are no scenic roadways or scenic vista views in or near the project area, so there would be no affect to such resources. Minor visual changes would result from the project and its Build Alternatives. The pres-ence of relocated utilities would be consistent with existing conditions, because they are already an exist-ing visual element within the project corridor. Therefore, their relocation would not alter the visual char-acter of views of and from the project corridor. Underground utilities would be relocated and would not be seen because they would again be placed underground, consistent with existing conditions. Slightly modified business entrances would not be very noticeable under both Build Alternatives, would be visu-ally consistent with existing conditions, and would not alter the appearance of these driveways. Similarly, ramp metering facilities and overhead signage already exists within the project corridor and relocating and modifying ramp meters and overhead signs would be visually consistent with existing conditions and would not result in notable changes to the visual appearance of the project corridor. Therefore, the most notable visual changes resulting from both Build Alternatives would be modifications to Mathilda Avenue, modifications to the SR 237 and US 101 on- and off-ramps, and associated vegetation removal. Both Build Alternatives would require removal of mature landscaping including trees, shrubs, and/ or vines at the following locations:


• At the US 101 interchange with Mathilda Avenue and between the westbound SR 237 ramps

and Moffett Park Drive to accommodate construction staging areas; • Within the Mathilda Avenue medians between Stations 47+00 to 51+00 and Stations 64+00

to 68+00 to accommodate lane modifications; • Within the SR 237 and US 101 interchange loops to accommodate staging, ramp modifica-

tions, and the clear recovery zone; • Between Weddell Drive and the northbound US 101 off-ramp to slightly shift and relocate the

sound wall; • West of Mathilda Avenue between Stations 46+00 to 49+50 to accommodate a new retaining

wall; and • East of Mathilda Avenue between Stations 49+00 to 56+00 to accommodate new lanes for

the SR 237 onramp and right hand turns onto Ross Drive. Mature landscaping is considered to be an attractive visual resource. Most of these areas would be re-planted as a part of the project. This includes portions of areas disturbed for construction staging that would be converted to vegetated, grassy bioretention basins while other portions would be re-land-scaped. Implementation of Avoidance, Minimization, and/or Mitigation Measures, Restore Highway Planting and Incorporate Bioretention Basins in Planting Design, would ensure that replacement planting and bioretention basins will be designed to blend with highway planting and create a cohesive landscape. As shown in the Simulated Views for KOP 1 (Figure 5) and KOP 2 (Figure 6), changes to the Mathilda Ave-nue corridor to accommodate turn lanes, bicycle facilities, and intersection improvements would result in slight alterations to views associated with the project corridor, but the changes would be largely con-sistent with the existing visual character of the multi-lane corridor. As shown in the simulations, changes to landscaping on both sides of the northbound US 101 on- and off-ramp to accommodate the reconfig-ured ramp, west of Mathilda Avenue to accommodate the new retaining wall; and east of Mathilda Ave-nue to accommodate new lanes for the SR 237 onramp and right hand turns onto Ross Drive would result in slight visual changes but views would still be largely vegetated with replacement plantings. As seen in the Simulated View for KOP 1, some vegetation removal would be needed to shift the ramps over to create a perpendicular connection for the proposed northbound US 101 on- and off-ramps to Mathilda Avenue. The relocated sidewalk and crosswalk would be slightly more visible from this vantage. New elements within this view would be the new traffic signal and a short, concrete barrier that would be seen on the ramp to separate traffic that is entering and exiting the ramp. Groundcovers and accent shrubs would be planted where the old ramp alignment is removed. These changes would create a slightly wider ramp but would allow for the existing northbound US 101 off-ramp to be removed and revegetated. The proposed southbound on- and off-ramps would also result in similar visual changes associated with creating a perpendicular intersection with Mathilda Avenue. These changes would be visible to roadway users on Mathilda Avenue and using the ramps and to pedestrians using sidewalks. Both Build Alternatives would involve the installation of one new retaining wall that would be located within the existing state ROW on the west side of Mathilda Avenue, north of the existing northbound US 101 loop off-ramp. The wall would be approximately 400 feet long and vary in height from 2 to 4 feet. The face of the wall would be adjacent to the existing ROW line and require vegetation removal to construct the wall. Removal of mature trees and shrubs west of Mathilda Avenue would slightly detract from views, but this area would be replanted with screening shrubs and the new retaining wall would not be visible from Mathilda Avenue because it would be even with or at a slightly lower elevation than the roadway,

Figure 4KOP Simulation Location Map


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Figure 5KOP 1 – Existing and Simulated Views for Build Alternatives 1 and 2


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as shown in the Simulated View for KOP 1. Views from the parking lot of businesses to the west of this new retaining wall would be slightly affected by tree removal. However, views of the wall would be screened by the existing privacy fencing along the parking lot that buffers views of the roadway and re-planting with screening shrubs would help to replace some of the screening that existing trees and shrubs provide. As shown in the Simulated View for KOP 2, the landscaping changes west of Mathilda Avenue are not very noticeable because they would blend in with the existing roadside vegetation. Avoidance, Mini-mization, and/or Mitigation Measure, Implement Aesthetic Treatments on Bridge Barriers, Sound Walls, and Retaining Walls, would ensure that the aesthetic treatment of any visible wall surface will be included. Both Build Alternatives would also require that the vegetation between Mathilda Avenue and Persian and Weddell Drives, between Stations 49+00 and 56+00, be removed to accommodate new lanes for the SR 237 onramp and right hand turns onto Ross Drive, which can be seen in the Simulated Views for KOP 1 and KOP 2. Removing this vegetation would slightly detract from views associated with the project under both Build Alternatives. As shown in the simulations, this area would be replanted with trees, shrubs, and groundcovers but it would take several years for this landscaping to mature and provide the same level of vegetative cover and shade. However, the landscaping would still be attractive and aide in maintaining a vegetated roadway corridor. These changes would be most visible to roadway users and pedestrians. It would not be readily visible to adjacent residences because the existing noise barrier along Mathilda Av-enue would remain and residential privacy fencing and residential landscaping helps to limit views. How-ever, at some locations, the tall evergreen trees growing in this landscaped area (refer to Existing View for KOP 2) would no longer be visible rising above the fence lines because they would be removed. The roadway widening would slightly increase the roadway surface area and roadway striping would be altered but would not substantially change the character of the roadway under both Build Alternatives. As shown in the Existing View for KOPs 1 and 2, cobbles pave the thinner portions of the median that is located between Stations 47+00 and 51+00 and mature trees are growing where the median is slightly wider. Under both Build Alternatives, as shown in the simulations, the median footprint would be slightly modified and cobbles would still be used to pave thinner portions of the median. As shown in KOP 1, the thinner median sections would not be wide enough to accommodate replacement plantings, which would result in views of a slightly wider roadway corridor. As shown in the simulation for KOP2, instead of trees, low-growing groundcover and accent shrubs would be planted in the median near the Mathilda Avenue intersection with Ross Drive, which would slightly alter views but would not substantially alter the visual character of the project corridor. The medians from the US 101 ramps and south to Almanor Avenue and north of Ross Drive would be slightly reconfigured, but would remain paved with cobbles and concrete, consistent with existing views. However, wider portions of theses reconfigured medians would also be planted with low-growing groundcover and accent shrubs. This would increase the amount of plantings within medians under both Build Alternatives. In addition, while trees would also be removed from the median located between Stations 64+00 and 68+00, both Build Alternatives would include replacement tree plantings within this median. The primary difference between Build Alternatives 1 and 2 is that the DDI configuration associated with Build Alternative 2 creates slightly more areas within which low-grow-ing groundcover and accent shrubs would be planted north of Ross Drive for a slightly greener view within this portion of the project corridor. Pedestrian facilities along Mathilda Avenue would be very similar to existing conditions, under both Build Alternatives, and sidewalks would only be slightly shifted to accommodate turn lanes as shown in the Simulated Views for KOP 1 and KOP 2. Similarly, under both Build Alternatives, striping would be added to delineate bicycle facilities as shown in the simulations. Both Build Alternatives would have the same layout for bicycle facilities south of Ross Drive and the layouts to the north of Ross Drive would differ slightly due


to the diamond versus DDI configurations. South of Ross Drive, striping would be used to delineate the bike lanes. The existing concrete barrier on the Mathilda Avenue Bridge over US 101 that separates vehic-ular from pedestrian traffic would be removed. A bike lane would be on both sides of the bridge, separated from traffic only by striping. In addition, the sidewalk along the southbound lanes of the bridge would be removed and only the sidewalk along northbound lanes of the bridge would remain, separated from traffic by the new bike lane. The outermost bridge barrier would be replaced with a new barrier. This would slightly alter views on the bridge by removing the intermediate barrier between roadway travel lanes and sidewalks and using roadway striping in place of the barrier. Avoidance, Minimization, and/or Mitigation Measure, Implement Aesthetic Treatments on Bridge Barriers, Sound Walls, and Retaining Walls, would ensure that the aesthetic treatment of any visible barrier surface will be included. Regardless of Build Alternative, bicycle facilities to the north of Ross Drive would have the same visual character that is asso-ciated with striping to delineate the bike lanes. Bicycle facilities associated with the project would increase recreational viewer access because bicycle facilities within the existing project corridor are limited. The SR 237 ramp connections to Mathilda Avenue would also result in small areas of vegetation removal that would be needed for the ramp reconfigurations and these changes are primarily associated with the westbound SR 237 ramps. However, shifting the westbound off-ramp under Build Alternative 1 to follow the current alignment of Moffett Park Drive creates a newly available space for planting in the area where the old ramp segment would be removed. Build Alternative 2, in a similar fashion, would remove the connection of Moffett Park Drive to Mathilda Avenue between Mathilda Avenue and Bordeaux Drive and this area would be planted. Both Build Alternatives would provide bicycle facilities between Mathilda Av-enue and Bordeaux Drive, in a very similar connection design. Both Build Alternatives would also connect Moffett Park Drive to Bordeaux Drive, in the same manner, to maintain vehicular access to Mathilda Ave-nue via Innovation Way. The westbound SR 237 on-ramp would be slightly reconfigured under both Build Alternatives. Build Alternative 1 would have a grassy bioretention area while Build Alternative 2 would provide more room for landscaping, in addition to a smaller, grassy bioretention area. The diamond versus DDI configurations associated with Build Alternatives 1 and 2, respectively, would result in a similar visual character along Mathilda Avenue. While there would be a visible difference in traffic patterns, both Build Alternatives would have signalized intersections, a similar width, a similar num-ber of lanes, lane striping and directional arrows, bicycle and pedestrian facilities, medians, and roadway signage. This would result in a very similar visual character for both Build Alternatives even though, as described above, Build Alternative 2 would have slightly more planted areas. Views from SR 237 and US 101 would not be greatly altered by either Build Alternative. Under both Build Alternatives, roadway users on the freeways would quickly pass by the interchanges. At highway speeds, viewers would notice changes resulting from the vegetation removal. Implementation of Avoidance, Min-imization, and/or Mitigation Measure, Restore Highway Planting, would ensure that infill plantings will be provided to further supplement replacement plantings proposed under the Build Alternatives and create a visually cohesive highway landscape. The eastbound SR 237 on- and off-ramps would not result in visu-ally apparent changes when seen in passing on the freeway because changes would primarily be lane striping occurring further up the ramps, closer to the intersection with Mathilda Avenue. Views from west-bound SR 237 would be slightly visible in passing but would be of slightly wider ramp exits and altered lane striping to accommodate an addition off-ramp lane. From US 101, there would be noticeable visual changes due to hardscape changes associated with ramp reconfiguration, landscape changes associated with vegetation removal, the installation of replacement plantings under both Build Alternatives, and changes resulting from the modification and installation of


safety barriers. As shown in the Simulated View for KOP 3 (Figure 7), the southbound US 101 off-ramp would be slightly wider and the off-ramp intersection with Mathilda Avenue would be a little more ex-posed. The wider ramp would slightly increase the amount of visible pavement and make it so that passing traffic on Mathilda Avenue would be a little more visible from this vantage. As shown in the foreground of the simulation, the most notable changes from this vantage would be associated with vegetation re-moval along the right side of the ramp. Removing the existing mature trees and shrubs and replanting this area with shorter shrubbery would expose and create more direct views of the office building, parking lot, parked cars, and fencing located at 525 Almanor Avenue which, as shown in the simulation, would be visible above the shorter replacement plantings. A limited amount of vegetation would also be removed to the left of the ramp to accommodate the ramp realignment that would be replanted with low-growing groundcovers. In addition, portions of existing vegetation within the ramp loop, not visible within the simulation behind existing vegetation to remain, would be affected by the project. However, most of these areas would be replanted with low-growing groundcovers and shrubs, as part of the project, except for within the clear recovery zone and in the areas that would be converted to bioretention basins. While replacement plantings proposed under the Build Alternatives would aid in improving project aesthetics, implementation of Avoidance, Minimization, and/or Mitigation Measure, Restore Highway Planting, would ensure that infill plantings will be provided to further supplement proposed replacement plantings and further improve project aesthetics. The bioretention basins would not be visible to viewers from the vantage of KOP 3 due to screening from existing and newly planted trees and shrubs, as illustrated by the simulation. The bioretention basins would mostly be seen by roadway users traveling on the US 101 ramps who would see sunken, grassy depressions that would hold water for short periods of time until the water infiltrates or enters the drain-age system. Implementation of Avoidance and Minimization Measure Incorporate Bioretention Basins in Planting Design, would use design means to blend the bioretention basins with the overall highway plant-ing, thus improving project aesthetics. Similar visual changes associated with vegetation removal, replacement plantings, and bioretention ba-sins would be seen when traveling on northbound US 101. Reconfiguration of the existing northbound US 101 off-ramp to northbound Mathilda Avenue would occur in the project area that corresponds to the Classified Landscaped Freeway portion of US 101. Replacement plantings would occur in this area. Con-sequently, views of this section of US 101 would not be greatly affected and the replacement planting would serve to retain Classified Landscaped Freeway designation. In addition, landscaping would be planted where the northbound loop off-ramp is removed, increasing the overall amount of landscaping associated with the interchange. Implementation of Avoidance, Minimization, and/or Mitigation Meas-ure, Restore Highway Planting, would ensure that additional plantings will be provided to supplement replacement plantings proposed under the Build Alternatives and create a visually cohesive highway land-scape. The modified outer barrier along the Mathilda Avenue Bridge over US 101 and barriers along the ramps, placed to separate traffic traveling in opposite direction, would be visible from the vantage of KOP 3, as shown in the Simulated View . Avoidance, Minimization, and/or Mitigation Measure, Implement Aesthetic Treatments on Bridge Barriers, Sound Walls, and Retaining Walls, would ensure that the aesthetic treat-ment of any visible barrier surface will be included. This would ensure that changes resulting from the outer bridge barrier would not be visually apparent when seen in passing on the freeway because the changes would be consistent with transportation corridor aesthetics. The barrier along the ramp would be hard to seek out and focus upon in passing at fast freeway speeds but would be visible to roadway


users on the ramps as they drive past the barrier. As shown in the simulation, new lane striping on the ramps would be consistent with existing visual conditions and would not stand out. The sound wall between Weddell Drive and the northbound US 101 off-ramp would be replaced. The new wall would be the same height and would be shifted three feet towards Weddell Drive to accommodate the slightly wider ramp at this location. This would not allow enough space on the Weddell Drive side of the wall to replant the creeping vines that would be removed during construction. Therefore, the bare wall surface would remain visible along this affected segment. While this is a relatively short segment of sound wall, this would negatively affect views seen from multi-family residences located along this portion of Weddell Drive and as seen by pedestrians, recreationists, and roadway users using Weddell Drive and its associated sidewalks. These viewers would now see a stark wall surface, instead of a more pleasing, vegetated wall surface. It would also detract from views seen by roadway users along us 101 and the northbound US 101 off-ramp, although briefly since viewers tend to pass this location quickly. The re-placed sound wall would use materials, colors, and texture that improve its aesthetic quality and comple-ment the existing surroundings. Avoidance, Minimization, and/or Mitigation Measure, Implement Aes-thetic Treatments on Bridge Barriers, Sound Walls, and Retaining Walls, would ensure that aesthetic treat-ment of the visible sound wall surfaces will be included. The project would result in a nominal increase in daytime glare by increasing the paved area and by re-moving some of the mature roadside vegetation that provides shade. However, the pavement would be grey, similar to existing conditions, which would reduce glare, and mature roadside vegetation would re-main along the ROW to provide some shade. In addition, while it would take a few years to mature and provide the same level of shading, new highway and street planting would be provided within the project corridor. Therefore, the project would not create a new source of substantial glare that would adversely affect daytime or nighttime views in the area. Both Build Alternatives propose very similar changes to signalized intersections and street lighting. The Mathilda Avenue intersections with Innovation Way, Moffett Park Drive, SR 237 West, SR 237 East, Ross Drive, and Almanor Avenue; and the Innovation Way intersection with Moffett Park Drive are signalized. Under both Build Alternatives, the signal at Mathilda Avenue and Almanor Avenue would not be affected; the signal at Mathilda Avenue and Moffett Park Drive would be removed; the Mathilda Avenue signals at Innovation Way and Ross Drive and at Innovation Way’s intersection with Moffett Park Drive would be modified, including the associated light rail crossing signals and facilities; the Mathilda Avenue signals for westbound and eastbound SR 237 would be removed and new signals would be installed for the relocated ramp entrances; and new traffic signals would be installed at the Mathilda Avenue intersection with north-bound and southbound US 101. Signal modification and the overall contribution of one additional signal-ized intersection compared to existing conditions would result in an inconsequential increase in lighting from signals in an area that is already well-lit. Under both Build Alternatives, the existing overhead cobra street lighting would also need to be modified to accommodate the new, slightly expanded roadway cor-ridor and reconfigured ramps. Lighting would be relocated where the widened corridor would affect ex-isting light posts along the edge of the roadway and ramps and within the median near Moffett Place. In addition, lighting would be enhanced for security and safety purpose increasing the amount of lighting within the corridor. While improving safety, the increased lighting level could negatively affect nearby roadway neighbors if not properly designed. Lights can negatively affect humans by increasing nuisance light and glare, in addition to increasing ambient light glow, if shielding is not provided and blue-rich white light lamps (BRWL) are used (International Dark-Sky Association 2010a, 2010b, 2015). This would result in a substantial source of nighttime light and glare that could adversely affect nighttime views in the area.


Avoidance, Minimization, and/or Mitigation Measure, Apply Minimum Lighting Standards, would ensure that adverse effects associate with lighting are reduced.

No-Build Alternative Under the No-Build Alternative, the project would not be constructed and there would be no visual im-pacts on the existing visual character, visual quality, or affected viewer groups.

AVOIDANCE, MINIMIZATION, and/or MITIGATION MEASURES Avoidance, minimization, and/or mitigation measures have been identified and can lessen visual impacts caused by the project. Also, the inclusion of aesthetic features in the project design previously discussed can help generate public acceptance of a project. This section describes additional avoidance, minimiza-tion, and/or mitigation measures to address specific visual impacts. These will be designed and imple-mented with concurrence of the District Landscape Architect. The following measures to avoid or minimize visual impacts will be incorporated into the project:

Implement Aesthetic Treatments on Bridge Barriers, Sound Walls, and Retaining Wall. The pro-ject will incorporate architectural treatment on new bridge barriers, sound walls and the visible side of the retaining wall.

Restore Highway Planting. A restored highway landscape will be provided within the interchanges of S.R 237 and U.S. 101 with Mathilda Avenue. A cohesive highway planting design, including additional plantings in areas not directly impacted by project construction, will ensure that re-placement plantings are integrated with the existing landscape to meet community expectations. A plant establishment period of three (3) years will be provided to ensure that new planting ma-tures.

Incorporate Bioretention Basins in Planting Design. The design of bioretention basins will be in-tegrated with the overall highway planting design, using techniques such as landform grading and/ or the incorporation of varied plant materials.

Apply Minimum Lighting Standards. All artificial outdoor lighting and overhead street lighting will be designed to have minimum impact on the surrounding environment. Design measures used to reduce light pollution will use the technologies available at the time of project design to allow for the highest potential reduction in light pollution. Such measures will include the use of down-cast, cut-off type fixtures that are shielded and that direct the minimum necessary light only to-ward objects requiring illumination.

Minimize Fugitive Light from Portable Sources Used for Construction. At a minimum, the con-struction contractor shall minimize project-related light and glare to the maximum extent feasi-ble, given safety considerations. Color-corrected halide lights will be used. Portable lights will be operated at the lowest allowable wattage and height and will be raised to a height no greater than 20 feet. All lights will be screened and directed downward toward work activities and away from the night sky and highway users and highway neighbors, particularly residential areas, to the maximum extent possible. The number of nighttime lights used will be minimized to the greatest extent possible.


CONCLUSIONS Build Alternatives 1 and 2 would result in similar visual impacts. Both Build Alternatives would slightly widen Mathilda Avenue and modify the SR 237 and US 101 interchanges with Mathilda Avenue. Changes and modifications associated with sound walls, barriers, signage, ramp metering, lane striping, utility re-locations, lighting, signalization, and bicycle and pedestrian facilities would be very similar under both Build Alternatives. All of these project features are existing corridors elements. Consequently, changes to these elements associated with roadway reconfiguration would not greatly alter the visual character of the project area. Additionally, light and glare affects would likely be minimal. Although mature trees and shrubs would be removed under Build Alternatives 1 and 2, both Build Alternatives would replant medi-ans, roadside locations east and west of Mathilda Avenue, and the areas within the interchanges. Restor-ing the highway landscape will enhance the proposed replacement planting and minimize visual impacts from the loss of mature vegetation, especially trees and vines that cannot can be replaced in their original locations. The restored highway planting can be expected to compensate for vegetation loss within 5 years of installation. While there would be a visible difference in traffic patterns, the diamond versus DDI configurations asso-ciated with Build Alternatives 1 and 2, respectively, would result in a similar visual character along Mathilda Avenue. The primary difference between Build Alternatives 1 and 2 is that the DDI configuration associated with Build Alternative 2 creates slightly more areas within which low-growing groundcover and accent shrubs would be planted north of Ross Drive for a slightly greener view within this portion of the project corridor, compared to Build Alternative 1. The Avoidance, Minimization, and/or Mitigation Measures would improve the aesthetics of built project features, provide attractive landscaping, reduce the effects of nighttime construction, and reduce light and glare impacts from lighting enhancements. With the incorporation of the specified minimization measures, the proposed Build Alternatives will not have an adverse significant impact.

References

Caltrans (California Department of Transportation). 2016. List of Officially Designated County Scenic Highways. Available: <http://www.dot.ca.gov/hq/LandArch/16_livability/scenic_highways/sce-nic_hwy.htm>. Last updated: May 5, 2015. Accessed: February 2, 2016.

———. 2014a. Classified "Landscaped Freeways" - November 12, 2014. Available: <http://www.dot.ca.gov/hq/LandArch/16_la_design/classified_ls_fwys/pdf/class_ls_fwy.pdf>. Last updated: November 12, 2014. Accessed: February 29, 2016.

———. 2014b. Outdoor Advertising Act and Regulations - 2014 Edition. Available: <http://www2.dot.ca.gov/oda/download/ODA_Act_&_Regulations.pdf>. Last updated: January 24, 2014. Accessed: February 29, 2016.

Federal Highway Administration. 1988. Visual Impact Assessment FOR Highway Projects. (FHWA-HI-88-054.) USDOT (US Department of Transportation), 1988.

International Dark-Sky Association. 2010a. Seeing Blue. April. Nightscape 80: 8-12. Available: <http://www.darksky.org/assets/documents/SeeingBlue.pdf>. Accessed: June 14, 2015.

http://www.dot.ca.gov/hq/LandArch/16_livability/scenic_highways/scenic_hwy.htm

http://www.dot.ca.gov/hq/LandArch/16_livability/scenic_highways/scenic_hwy.htm

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———. 2010b. Visibility, Environmental, and Astronomical Issues Associated with Blue-Rich White Outdoor Lighting. Available: http://www.darksky.org/assets/documents/Reports/IDA-Blue-Rich-Light-White-Paper.pdf. Document date: May 4, 2010. Accessed: June 14, 2015.

———. 2015. IDA Issues New Standards on Blue Light at Night. April. Nightscape 94: 10. Available: <http://www.darksky.org/assets/documents/Nightscape/IDA_April2015_LowRes.pdf>. Ac-cessed: June 14, 2015.

City of Sunnyvale. 2011. Sunnyvale General Plan – Consolidated in 2011. July 2011. Sunnyvale, CA.

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