LA-SF day trips will be possible, bearing in mind that LA-SF in 2 hours 57 minutes is for a stopping train (that would be averaging 210km/h, when I would say that it should be possible to average 285). 1/4 of flights on the route are delayed by OVER AN HOUR while in practise HSR is as close to seldom as humanely possible. It is far quicker than flying and makes cars look completely ridiculous. Terrorism will be easy to deter. Terrorists on trains are fairly easy to spot and trains don't have to land. To place a bomb on the track you have to do the following:
1. Climb over the 1st electric fence.
2. Climb up the embankment or viaduct with anti-climb paint on it.
3. Climb over the second electric fence.
4. Climb over the electric rails
5. Place the bomb on the track
In cab signalling will immediately stop a train anyway.
In China and Japan, railways go 200 km/h. Well who says 'Merica can't do it? This railway is required to not only ease traffic and make transportation quicker, but to show America is 'Merica where we are the best around and nothings ever gonna take us down. I had to do that pun. For a terrorist to plant a bomb on a train, you'd have to be one intelligent person. It's like trying to cross the demilitarized zone in the Korea's it's very improbable to do.
The California State has the highest population in the US, and although not in density, most of the population lies in San Fran county and LA county. Cars are not the most efficient in transportation since usually a car with 5-7 seats, only 1-2 seats are used per vehicle. With the rising population and new teens every year with a car, its going to be pretty congested with traffic. We can widen roads but that will won't be enough and will just take up more residential space.
A high speed train in California seems like an excellent idea. A high-speed train would overall ease congestion, save gas, reduce air/noise pollution, save time(high-speed), and advance California as a whole if not the whole nation.
The bullet train is a perfectly fine idea. However, that $68.4 billion dollars can be used elsewhere. Why not improve the trains we already have? You say it will reduce pollution, and that may be true, but for the time being, the actual construction of the train is polluting a lot and harming the environment. Besides, who is going to buy a ticket if you can buy a plane ticket for less?! It's simply not worth the costs.