is your most complete source of information on the City of Sunnyvale, CA,  proposed Mary Avenue Extension (MAE) (Bridge, Overpass, whatever), its Environmental Impact Report (EIR) and the litigation seeking to decertify the EIR. Home 

Mary Avenue Wiki

MAE -- The Project and EIR's in General Comments about the EIR Comments about the MAEP City Council Meeting 10/28/08 and start of Litigation The Litigation Continued (Under Construction)

MARY AVENUE -- THE PROJECT and Environmental Impact Reports (EIR) In General


Project Description Provided by the City of Sunnyvale as part of the MAEP Environmental Scoping Meeting of Feb 21, 2007 Project Description provided by Dave Whittum as part of his comment in 09/07 A history of the MAE project written by Eleanor Hansen and Tammy Salans. Environmental Impact Reports (EIR) In General


According to the Draft Environmental Impact Report (DEIR)1 this project proposes a 1/2- mile long, 80-feet high bridge to extend Mary Avenue over US 101, SR 237, and a VTA Light Rail Station into Moffett Park, in proximity to a new development by Jay Paul Company, a privately held real-estate firm.2,3 The alignment puts the new construction below the Moffett flight path, over the Hetch Hetchy aqueduct and through an area containing a prehistoric Ohlone burial ground. A few blocks to the south Mary Avenue crosses at-grade the Caltrain/Union Pacific railroad tracks, which see 96 commuter trains each weekday, and an indeterminate number of freight trains in the evening and early morning. The project site, while not clearly defined by the DEIR, appears to lie within Sunnyvale, California.

A "realistic" type diagram from the Mary Avenue Extension Draft Environmental Impact Report is Shown Separately. 

The project description provided in the filing with the State Clearinghouse is:4,5

The project proposes to extend Mary Avenue from its current terminus at Almanor Avenue north, over US 101 and SR-237, to Eleventh Avenue at E Street. Currently, Mary Avenue is an approximately 5.6-mile, two- to six-lane, north-south arterial that extends north from Homestead Road in south Sunnyvale and terminates at Almanor Avenue just south of US 101. The proposed extension includes a 0.3 mile long bridge structure over the two freeways and light rail transit (LRT) tracks. North and south of the bridge, the roadway extension would be supported by embankments. The bridge structure would have four traffic lanes, a raised median, sidewalks, and bike lanes. In addition, the project includes signalized intersection improvements at the intersection of Mary Avenue and Almanor Avenue, and at the northerly connection of Mary Avenue to the Eleventh Avenue and E Street intersection.

The purpose of this project is not clearly defined in the DEIR. On p.6 one finds

The purpose of the Mary Avenue extension is to help alleviate regional operational deficiencies by providing an alternative north-south connector to lands north of US 101 and SR 237 (including the Moffett Park Area; and alleviating existing and future traffic congestion in the Moffett Park Area and other areas adjacent to Mary Avenue.

The meaning of “other areas adjacent to Mary Avenue” is unclear. Elsewhere the DEIR states that the purpose is to “help alleviate regional operational deficiencies by providing a vehicular, pedestrian and bicycle alternative to the existing north-south connections in the City.” [DEIR p.15]. The DEIR does not clearly state why there are “operational deficiencies”, nor why they “are expected to worsen”. [DEIR p.15]

Meanwhile, other documents prepared by the City, and not cited in this DEIR imply that vehicular traffic is due in part to new Moffett Park developments.6,7 For example, a Moffett Park Business and Transportation Association document states:8 “The Mary Avenue project will extend Mary Avenue across U.S. 101 and SR 237 in the northern part of the City in order to address anticipated traffic congestion on the City’s major north-south roadways as well as to improve access to Moffett Industrial Park.” While it is not clearly stated in the DEIR, public comments reflect a widely-held belief that the purpose of this project is to facilitate commuter traffic into Moffett Park.

Since Mary Avenue, with an overpass, would provide a straight-shot into Moffett Park,the conclusion many residents have reached is that this project would result in high levels of traffic on Mary Avenue into the millions of square feet of new office space planned or in-progress in this business park. The DEIR does not provide substantial evidence to contradict this intuitive conclusion.

In fact, the Moffett Park DEIR Transportation and Circulation analysis makes clear that its traffic assumptions include a future Mary Avenue Extension.9 [Moffett Park Specific Plan Environmental Impact Report, p.3.12-22]:

The future land uses in the City were estimated by the City of Sunnyvale Planning Department. The future land use assumptions are based on buildout of allowable and likely development under the City of Sunnyvale General Plan and the associated zoning. In the Moffett Park area, the amount of development allowable under General Plan zoning was evaluated for each vacant parcel or each parcel where development was likely. Total buildout of the General Plan Conditions would result in approximately 18 million square feet of R&D development in Moffett Park.These future land use assumptions were also input to the model to determine the 2020 General Plan Conditions. The future model also assumes completion of the Mary Avenue Extension from Maude Avenue, over US-101 and Route 237, to H Street in the Moffett Park area. All roadway projects that are committed in the Valley Transportation Plan (VTP) Capital Investment Program in Santa Clara County have also been included in the model. In the Sunnyvale area, these improvements include HOV lanes on Central Expressway and Route 237, and interchange improvements at the junctions of Route 85 with US-101 and Interstate 280. Again, the model assigned all trips over the roadway network and the turn movement volumes at the study intersections were obtained. The General Plan Conditions were projected to generate about 6,100 more trips in the AM peak hour and about 5,400 more trips in the PM peak hour for Moffett Park Specific Plan area compared to Existing Conditions.

For later reference, note that the narrative indicates that accuracy of estimates was sacrificed to “evaluate the most conservative case”:

The difference between the 1998 and 2020 General Plan Conditions model volumes for each study freeway segment was calculated to determine the increment volumes. This traffic growth increment was added to the existing freeway volumes for each respective segment to estimate [1]the 2020 General Plan Conditions freeway volumes. For segments which had negative increments when the projected 2020 traffic levels were less than existing levels, the traffic volumes were assumed to remain at the higher existing volumes in order to evaluate the most conservative case.

Thus the Moffett Park Specific Plan DEIR does not provide an accurate basis for assessing the purpose and need of the Mary Avenue Extension, as it intentionally overestimates future traffic volumes. 


1 see also

2 , 350 California Street, Suite 1905, San Francisco, CA 94014, Tel: (415) 263- 7400, Fax: (415) 362-0698,

3 “Jay Paul Co. begins work on Moffett Towers”


5 6 “Moffett Park Specific Plan DEIR” and see ning/Moffett+Park.htm


363C3 1CE9EE3/0/MoffettParkSpecificPlan.pdf Moffett Park Specific Plan

8 Moffet Park EIR

9 8D6788071E75/0/MPEIRCh3 12Transportation.pdf