Edited sentence: However, more compelling is taking cars off the road by getting from San Diego to LA in 35 minutes, Irvine to LA in 20 minutes even in rush hour.If existing Caltrain, Metrolink, Altamont, and Coaster services were converted to high speed rail, new land would not be needed, and some existing stations could be used, $20 billion could be saved (tunneling through mountains isn't cheap) for other things like widening Interstate 5, making it safer for all.One alternative that would cost less than half the price and include all major cities is to build two unlinked systems, one for Northern California and one for Southern California, deleting the expensive middle section going through vast nothingness of San Joaquin Valley.One is it requires a choice between two routes, San Francisco Bay Area or Sacramento, and whoever gets left out will probably be inclined not to support the bill politically.People don't go LA-SF every day for work anyway, so that traffic is tiny compared to commuters.Similarly, San Jose to San Francisco in 20 minutes, and San Francisco to Sacramento in 35 minutes, even in rush hour.The current plan has a few faults, political and budgetary.The rationale behind this is, we already have LA-SF/Sac services that can do  it in 2-3 hours, called airplanes