That's amazing. Caltrain is the "tech" industry commute option. That doc says that "minority" (non-white) ridership share is growing, but it's actually Asian/Indian growing and black/hispanic shrinking.

You are right that Caltrain isn't a good example, but the bus transit systems of the Bay Area's suburban locales, like SamTrans, do reflect the GP's comment. SamTrans' 2011 median rider income was $36000, 64% had no car, and 33% were youths.

http://www.samtrans.com/Assets/_SSP/archives/2011/July_Open_...

These stats are somewhat skewed by the fact that cold-weather night bus routes are mostly populated by homeless who are there for shelter/warmth rather than transportation (I can't speak to SamTrans specifically, but it is the case for VTA). VTA likes it, as it boosts their census artificially.