The VTA has published the draft EIR for phase 2 of the San Jose BART extension. Phase 2 would extend the line starting from Berryessa, through the downtown area, and terminating (for now) at Santa Clara Caltrain. The projected cost is more than $4.7 billion.
Like most EIR’s, it is extremely long. But you can skip to this one chart, which tells all that you need to know about the cost-effectiveness:
In other words, the VTA will spend over $4.7 billion to generate just 14,619 new transit trips. Counting operating subsidies, that is more than $50 per trip.