As for infrastructure, the City has not, in my mind, adequately addressed the problem the will accompany the parking and noise. I have read the CEQA report in which the environmental experts do feel that there will not be noticeable environmental impact, but one only has to attend an evening of fireworks at Great America or be at a crowded conference in the area to know that the surface streets and lights are not yet prepared for an influx of 20-40,000 additional vehicles. I'm sure it will be addressed over time, but there will undoubtedly be growing pains, and I'm glad I'm way over here in Sunnyvale so that I won't personally be impacted by the stadium when it does arrive.
So right now...no, the area is not prepared for the stadium or the impact associated with the stadium activities. However, when the stadium is fully operational, given the information noted with the plans, I have no doubt that the situation will not be ideal, but will certainly be manageable.
21,000 parking places - A major event causes a surge in traffic which will not be completely handled. Driving by Shoreline Park when there is a concert provides a nearby example. The new stadium appears to have more freeway entry/exit points but adding 20,000 cars to existing traffic will surely cause traffic problems.
Recent years have had decreased jobs which in turn reduced traffic. Silicon Valley was recently ranked #1 for economic growth. Traffic will increase with growth.
As for the more general question about affects on neighborhoods: The stadium will probably have different affects on different people. Young people who want excitement and aren't worried about "urban" traffic density may be attracted. Families who want to have a peaceful home and few traffic problems won't be attracted. On the whole it will probably put a slight drag on single family homes but could create additional demand from buyers with special interests.
Top 3 agent nationwide at Keller Williams Realty
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Over 1,000 home sales in Santa Clara and San Mateo Counties
Extra good news, property values will increase. And, who knows, maybe you can charge $20 for Parking in your driveway (wink, wink).