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

The older History 1983-1991

The newer History 2007-2009


[These older history sections written by Eleanor Hansen]

As explorers in earlier times searched for the Northwest Passage -- from the middle of the North American continent to the Pacific Ocean, or Crusaders and the Monty Python for the Holy Grail, so planners have sought to find a way to improve the access to northern areas of Sunnyvale to permit higher density business development. Although earlier studies indicate that this was for the benefit of workers at Lockheed-Martin, it appears that in later years (with the decrease in the number of workers at Lockheed-Martin), that this was to allow new development, such as provided for by the Moffett (Business) Park Specific Plan.

The first presentation of a Mary Avenue Extension is, as far as the author(s) know in the City of Sunnyvale North-South Corridor Study (1983). In this study, however, the planned overpass over Highway 101 and State Route (SR) 237, had immediate access to SR 237 at its southern terminus at Mary and Almanor Avenues. [For a schematic of this bridge, you can see the Alternative 1 Diagram] So there was little expected effect on traffic in other parts of Sunnyvale.

The second presentation of a Mary Avenue Extension was in the North-South Corridor Study Phase II (1987). This study contained the following discussion:


The Phase 1 recommendations for the extension of Mary Avenue included grade separations at the intersections of Mary Avenue with Central Expressway and the Southern Pacific Railroad. Recent development along Mary Avenue in the vicinity of Central Expressway has been residential. Exist­ing development south of Evelyn and the Southern Pacific tracks is also residential. Therefore, extension of Mary Avenue into Lockheed property would likely result in in­creased traffic through residential areas.

The extension of Mary Avenue with grade separations at Central Expressway and at Evelyn could attract as much as 13,900 vehicles per day. This would represent additional traffic on the existing segments of Mary Avenue. The estimated traffic is summarized in Table 4-5.




Average Daily Traffic (ADT)




With Mary Ave Extension



S of Evelyn Ave





S of Maude Ave





S. of SR 237





The area south of SR237 is industrial. The projected traffic in the segment would be acceptable. The segment south of Maude is bordered by new high-density industrial develop­ment. While the increase in traffic is significant in this segment, it could be accommodated provided that proper miti­gation measures are incorporated into the design. However, the growth in traffic south of Evelyn would impact older, established neighborhoods. It is anticipated that mitiga­tion of the impacts south of Evelyn may be particularly difficult. For this reason it is not recommended that the grade separation of Mary Avenue at Evelyn and the Southern Pacific Railroad tracks be included in any of the Mary Avenue Extension alternatives. Elimination of the Evelyn grade separation should help to discourage use of Mary Avenue south of Evelyn as a major commute route and help maintain its existing character.

HISTORY -- 1990-1991

As is apparently usual with City of Sunnyvale Traffic Studies, there appears not to have been much resident review or reaction to the North-South Corridor Study Phase II (1987) and the plans for the Mary Avenue Extension continued. The next relevant document appears to the Traffic Analysis for the Alternatives for the Routes 101/237/Mathilda Avenue Mini-Triangle Study Area (April 1990) prepared for the SC County Traffic Authority and the CA Department of Transportation. This (again) showed a Mary Avenue Extension with a southern terminus at Mary and Almanor Avenues. In that study, the following growth in jobs was assumed:

Table 4-1




1990 [Existing]

2010 [Projected]

West of Mathilda Ave




Between  Mathilda and Carribean








Total possible daily trips




Given the wording in the study,the author believes that the above numbers do not account for vendors and contractors that would be coming into area to work.

Several diagrams in the study indicate that the projected average traffic volumes in year 2010 would be 32,160 {both directions together} on Mary Avenue south of Almanor with the extension or flyover. Other diagrams indicate that with the flyover or extension, the projected peak hour volumes were projected to be 1,380 northbound am and 1,660 southbound pm, on Mary Avenue south of Almanor.  

The just above discussed study was followed by the Mary Avenue Extension Project Study Report Draft for the City of Sunnyvale (May 1991), prepared by TJKM Transportation Consultants of Pleasanton, CA. This report on page 1 indicates that  "The proposed project consists of extending Mary Avenue northerly over Route 101 and State Route 237 to the vicinity of Jagels Road. The extension will serve as a reliever route for Mathilda Avenue. Approximately 32,000 vehicles will be served by the project by the year 2010. [bold added by editor] In a later section  (Page 6) , this report continued this discussion, "Approximately 2,000 vehicles in the peak ours (32,000 vehicles daily) would use the Mary Avenue Extension by the year 2010. On page 9, under section E., Impacts to Adjacent Land Uses on Mary Avenue, the discussion continues with "The area south of Route 237 to Evelyn Avenue is industrial, and south of Evelyn Avenue is established residential neighborhoods. …South of Evelyn Avenue, the traffic growth may be significant with as much as 5,000 to 10,000 additional vehicles daily. This margin of traffic growth would be undesirable along the residential neighborhoods…

It is the authors/editors(s) understanding based on conversations with long-time residents, that after the publication, discussion and review of this study, residents' reaction was such that the City Council at that time, set the project aside.