In the world of City Planning, "near" is considered 1-3 years, and "far" is considered anything after about 5 years. From start to finish a project takes approximately 3 years for plan check, plan approval, issuance of a building permit, construction, inspection, and completion. So a 3 year time line is still quite predictable, but a 5+ year time period is a lot harder to foresee both for the City as well as the community. If you are looking only for general information, each of the cities--Mountain View, Sunnyvale, Cupertino and Santa Clara--have City websites where you can see information about upcoming or pending buliding permit applications.
But, let me back up for a minute...every City from Cupertino to Mountain View to Santa Clara has a "general plan" in place for the areas within the community designated for commercial, residential, industrial and agricultural use. The general plan also specifies how these areas might change with a population change, so these Cities have, already preplanned, areas that might be "ripe" for expansion or demolition and upgrade. Because the city's general plan is quite extensive, to learn what "might" happen to a home for which you would be interested in purchasing, you will need to talk with a member of the City's planning department. If you're thinking in particular of buying in Santa Clara, then you have selected one of the very nicest and easiest planning divisions in the entire Valley, so the planners there can help you with general inquiries.
If you are worried about a specific structure or development coming to an area near a home you wish to buy, you can also get a lot of information specifically about the proposed development.
In addition to the City's general plan, any new building project must meet the provisions of the California Environmental Quality Act (CEQA...pronounced "see-kwa"). The Act requires developers wishing to make changes within the community to hold a series of hearings to allow input from the surrounding homeowners. CEQA also requires the developer to conduct a series of "tests" to determine how the project would impact the surrounding community and to publish and make publicly available these test results in a report called an "Environmental Impact Report" or "EIR". Homeowners who live near a proposed project may obtain copies of the EIR by contacting their planning department and this would go a long way to determinining if a specific project would be beneficial or harmful to your home's value.
I hope this helps answer your questions and gives you some valuable information on how projects are approved through City governments. I would suggest checking the websites or each of the cities for which you might be interested in buying and then talking with the planning department for more information.
Good luck and happy house hunting!
Grace Morioka, SRES, e-Pro
Agent/Facilitator, Community Forward Planning Consultant
Area Pro Realty
Tel (408) 426-1616
I'm happy to help you further offline, I was a news reporter covering cities and counties in CA for about 12 years (Sacramento Bee, etc).
Look for my new publication on short sales in early June!